[Android Software/Hacking General [Developers Only]] sorewinner:
Is your superuser root manager app compatible with CYM 13.0? It seems to only work on first install. After a few reboots, root requests are automatically denied, because the prompt only stays on-screen for 0.25s, which is too short to even draw the window, let alone the buttons. Uninstalling and reinstalling it doesn't change the behaviour.

ADB logcat:

08-11 04:51:15.299 13236 13236 D AndroidRuntime: Calling main entry com.android.commands.am.Am
08-11 04:51:15.307 744 1211 I ActivityManager: START u0 {flg=0x10000000 cmp=me.phh.superuser/com.koushikdutta.superuser.RequestActivity (has extras)} from uid 0 on display 0
08-11 04:51:15.339 13236 13236 D AndroidRuntime: Shutting down VM
08-11 04:51:15.389 744 995 I ActivityManager: START u0 {flg=0x10800000 cmp=me.phh.superuser/com.koushikdutta.superuser.MultitaskSuRequestActivity (has extras)} from uid 10134 on display 0
08-11 04:51:15.496 13251 13251 W Thread-561: type=1400 audit(0.0:66111): avc: denied { write } for name=".socket13232" dev="tmpfs" ino=181823 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:device:s0 tclass=sock_file permissive=0
08-11 04:51:15.513 10489 13251 I Superuser: Permission denied
08-11 04:51:15.513 10489 13251 I Superuser: java.io.IOException: Permission denied
08-11 04:51:15.513 10489 13251 I Superuser: at android.net.LocalSocketImpl.connectLocal(Native Method)
08-11 04:51:15.513 10489 13251 I Superuser: at android.net.LocalSocketImpl.connect(LocalSocketImpl.java:290)
08-11 04:51:15.513 10489 13251 I Superuser: at android.net.LocalSocket.connect(LocalSocket.java:130)
08-11 04:51:15.513 10489 13251 I Superuser: at com.koushikdutta.superuser.MultitaskSuRequestActivity$7.run(MultitaskSuRequestActivity.java:278)
08-11 04:51:15.716 10489 10489 W ruser:superuser: type=1400 audit(0.0:66112): avc: denied { getattr } for path="/dev/me.phh.superuser/.socket13232" dev="tmpfs"ino=181823 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:device:s0 tclass=sock_file permissive=0
08-11 04:51:15.727 744 1287 W ActivityManager: Finishing task with all activities already finished
08-11 04:51:15.727 744 1287 W ActivityManager: Duplicate finish request for ActivityRecord{646701f u0 me.phh.superuser/com.koushikdutta.superuser.MultitaskSuRequestActivity t40 f}
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66113): avc: denied { getattr } for path="/proc/1" dev="proc" ino=6724 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:init:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66114): avc: denied { search } for name="1" dev="proc" ino=6724 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:init:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66115): avc: denied { search } for name="1" dev="proc" ino=6724 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:init:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66116): avc: denied { getattr } for path="/proc/2" dev="proc" ino=90510 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66117): avc: denied { search } for name="2" dev="proc" ino=90510 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66118): avc: denied { search } for name="2" dev="proc" ino=90510 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66119): avc: denied { getattr } for path="/proc/3" dev="proc" ino=90511 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66120): avc: denied { search } for name="3" dev="proc" ino=90511 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66121): avc: denied { search } for name="3" dev="proc" ino=90511 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66122): avc: denied { getattr } for path="/proc/7" dev="proc" ino=90514 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66123): avc: denied { search } for name="7" dev="proc" ino=90514 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66124): avc: denied { search } for name="7" dev="proc" ino=90514 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66125): avc: denied { getattr } for path="/proc/8" dev="proc" ino=90515 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66126): avc: denied { search } for name="8" dev="proc" ino=90515 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66127): avc: denied { search } for name="8" dev="proc" ino=90515 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66128): avc: denied { getattr } for path="/proc/9" dev="proc" ino=90516 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66129): avc: denied { search } for name="9" dev="proc" ino=90516 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0
08-11 04:51:15.946 13259 13259 W toolbox : type=1400 audit(0.0:66130): avc: denied { search } for name="9" dev="proc" ino=90516 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:r:kernel:s0 tclass=dir permissive=0

I'm not sure if the problem is with the superuser app, or your root.