Note that professional graphics produces a superior chart than standard graphics. The control chart was constructed assuming that the process was in control. Yet three averages were beyond the control limits. We have therefore solid evidence that the process is not in control. The important thing is what happens next.
Control charts can identify the presence of a special cause.
People need to track down the root cause and remove it, ensuring that it does not recur. Every incident, change, or unusual circumstance should be logged on the control chart at the time point where it occurred. This is easy enough to do when the chart is being manually recorded, in real time. Many computer programs which claim to do SPC do not permit comments to be made on the chart - which shows they don't understand the purpose of the control chart. Control charts which are run off and filed away from the process producing the output are not being used properly.