Program: 81820
Project: 81820
Buggy source:
public void onTickInGame(){
  Minecraft mc=FMLClientHandler.instance().getClient();
  World world=mc.world;
  if (ConfigMisc.Misc_proxyRenderOverrideEnabled) {
    if (!(mc.entityRenderer instanceof EntityRendererProxyWeather2Mini)) {
      oldRenderer=mc.entityRenderer;
      EntityRendererProxyWeather2Mini temp=new EntityRendererProxyWeather2Mini(mc,mc.getResourceManager());
      mc.entityRenderer=temp;
    }
  }
 else {
    if ((mc.entityRenderer instanceof EntityRendererProxyWeather2Mini)) {
      if (oldRenderer != null) {
        mc.entityRenderer=oldRenderer;
      }
 else {
        mc.entityRenderer=new EntityRenderer(mc,mc.getResourceManager());
      }
    }
  }
  if (world != null) {
    checkClientWeather();
    weatherManager.tick();
    if (ConfigMisc.Misc_ForceVanillaCloudsOff && world.provider.getDimension() == 0) {
      mc.gameSettings.clouds=0;
    }
    if (WeatherUtilConfig.listDimensionsWindEffects.contains(world.provider.getDimension())) {
      sceneEnhancer.tickClient();
    }
    if (mc.ingameGUI.getChatGUI().getSentMessages().size() > 0) {
      String msg=(String)mc.ingameGUI.getChatGUI().getSentMessages().get(mc.ingameGUI.getChatGUI().getSentMessages().size() - 1);
      if (msg.equals("String_Node_Str")) {
        mc.ingameGUI.getChatGUI().getSentMessages().remove(mc.ingameGUI.getChatGUI().getSentMessages().size() - 1);
        mc.displayGuiScreen(new GuiEZConfig());
      }
    }
    float windDir=WindReader.getWindAngle(world,null);
    float windSpeed=WindReader.getWindSpeed(world,null);
    windDir=0;
    float give=30;
    float diff=Math.abs(windDir - smoothAngle);
    if (true && diff > 10) {
      if (smoothAngle > 180)       smoothAngle-=360;
      if (smoothAngle < -180)       smoothAngle+=360;
      float bestMove=MathHelper.wrapDegrees(windDir - smoothAngle);
      smoothAngleAdj=windSpeed;
      if (Math.abs(bestMove) < 180) {
        float realAdj=smoothAngleAdj;
        if (realAdj * 2 > windSpeed) {
          if (bestMove > 0) {
            smoothAngleRotationalVelAccel-=realAdj;
            if (prevDir < 0) {
              smoothAngleRotationalVelAccel=0;
            }
            prevDir=1;
          }
 else           if (bestMove < 0) {
            smoothAngleRotationalVelAccel+=realAdj;
            if (prevDir > 0) {
              smoothAngleRotationalVelAccel=0;
            }
            prevDir=-1;
          }
        }
        if (smoothAngleRotationalVelAccel > 0.3 || smoothAngleRotationalVelAccel < -0.3) {
          smoothAngle+=smoothAngleRotationalVelAccel * 0.1F;
        }
 else {
        }
        smoothAngleRotationalVelAccel*=0.80F;
      }
    }
    if (!Minecraft.getMinecraft().isGamePaused()) {
      ExtendedRenderer.foliageRenderer.windDir-=2;
      windSpeed=1.3F;
      float rate=0.005F;
      if (ExtendedRenderer.foliageRenderer.windSpeedSmooth != windSpeed) {
        if (ExtendedRenderer.foliageRenderer.windSpeedSmooth < windSpeed) {
          if (ExtendedRenderer.foliageRenderer.windSpeedSmooth + rate > windSpeed) {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth=windSpeed;
          }
 else {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth+=rate;
          }
        }
 else {
          if (ExtendedRenderer.foliageRenderer.windSpeedSmooth - rate < windSpeed) {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth=windSpeed;
          }
 else {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth-=rate;
          }
        }
      }
      float baseTimeChangeRate=60F;
      ExtendedRenderer.foliageRenderer.windTime+=0 + (baseTimeChangeRate * ExtendedRenderer.foliageRenderer.windSpeedSmooth);
    }
  }
 else {
    resetClientWeather();
  }
}

Fixed version (ground truth):
public void onTickInGame(){
  Minecraft mc=FMLClientHandler.instance().getClient();
  World world=mc.world;
  if (ConfigMisc.Misc_proxyRenderOverrideEnabled) {
    if (!(mc.entityRenderer instanceof EntityRendererProxyWeather2Mini)) {
      oldRenderer=mc.entityRenderer;
      EntityRendererProxyWeather2Mini temp=new EntityRendererProxyWeather2Mini(mc,mc.getResourceManager());
      mc.entityRenderer=temp;
    }
  }
 else {
    if ((mc.entityRenderer instanceof EntityRendererProxyWeather2Mini)) {
      if (oldRenderer != null) {
        mc.entityRenderer=oldRenderer;
      }
 else {
        mc.entityRenderer=new EntityRenderer(mc,mc.getResourceManager());
      }
    }
  }
  if (world != null) {
    checkClientWeather();
    weatherManager.tick();
    if (ConfigMisc.Misc_ForceVanillaCloudsOff && world.provider.getDimension() == 0) {
      mc.gameSettings.clouds=0;
    }
    if (WeatherUtilConfig.listDimensionsWindEffects.contains(world.provider.getDimension())) {
      sceneEnhancer.tickClient();
    }
    if (mc.ingameGUI.getChatGUI().getSentMessages().size() > 0) {
      String msg=(String)mc.ingameGUI.getChatGUI().getSentMessages().get(mc.ingameGUI.getChatGUI().getSentMessages().size() - 1);
      if (msg.equals("String_Node_Str")) {
        mc.ingameGUI.getChatGUI().getSentMessages().remove(mc.ingameGUI.getChatGUI().getSentMessages().size() - 1);
        mc.displayGuiScreen(new GuiEZConfig());
      }
    }
    float windDir=WindReader.getWindAngle(world,null);
    float windSpeed=WindReader.getWindSpeed(world,null);
    windDir=0;
    float give=30;
    float diff=Math.abs(windDir - smoothAngle);
    if (true && diff > 10) {
      if (smoothAngle > 180)       smoothAngle-=360;
      if (smoothAngle < -180)       smoothAngle+=360;
      float bestMove=MathHelper.wrapDegrees(windDir - smoothAngle);
      smoothAngleAdj=windSpeed;
      if (Math.abs(bestMove) < 180) {
        float realAdj=smoothAngleAdj;
        if (realAdj * 2 > windSpeed) {
          if (bestMove > 0) {
            smoothAngleRotationalVelAccel-=realAdj;
            if (prevDir < 0) {
              smoothAngleRotationalVelAccel=0;
            }
            prevDir=1;
          }
 else           if (bestMove < 0) {
            smoothAngleRotationalVelAccel+=realAdj;
            if (prevDir > 0) {
              smoothAngleRotationalVelAccel=0;
            }
            prevDir=-1;
          }
        }
        if (smoothAngleRotationalVelAccel > 0.3 || smoothAngleRotationalVelAccel < -0.3) {
          smoothAngle+=smoothAngleRotationalVelAccel * 0.1F;
        }
 else {
        }
        smoothAngleRotationalVelAccel*=0.80F;
      }
    }
    if (!Minecraft.getMinecraft().isGamePaused()) {
      ExtendedRenderer.foliageRenderer.windDir=smoothAngle;
      windSpeed=1.3F;
      float rate=0.005F;
      if (ExtendedRenderer.foliageRenderer.windSpeedSmooth != windSpeed) {
        if (ExtendedRenderer.foliageRenderer.windSpeedSmooth < windSpeed) {
          if (ExtendedRenderer.foliageRenderer.windSpeedSmooth + rate > windSpeed) {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth=windSpeed;
          }
 else {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth+=rate;
          }
        }
 else {
          if (ExtendedRenderer.foliageRenderer.windSpeedSmooth - rate < windSpeed) {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth=windSpeed;
          }
 else {
            ExtendedRenderer.foliageRenderer.windSpeedSmooth-=rate;
          }
        }
      }
      float baseTimeChangeRate=60F;
      ExtendedRenderer.foliageRenderer.windTime+=0 + (baseTimeChangeRate * ExtendedRenderer.foliageRenderer.windSpeedSmooth);
    }
  }
 else {
    resetClientWeather();
  }
}