It looks like you have been editing sections of the part and not using Update All when saving the changes so U1 is now built from different revisions of the CPU symbol, certainly one of the sections, CPU_6, is on it's 7th edit, and the others are different - hence the message. Use File>New>Library, save the created library to a known name and location, rather than the defalut. Go to the Design Cache, locate the latest CPU part, probably CPU_6 but could be later (CPU_7 and up), control+C on the part, go to the library just created, select the library name and Control+V to paste the part, Save the Library, rename the part to CPU and save the library again. Back in the Design Cache, right-click on each CPU_x entry and select Replace Cache, browse to the library just created and select the CPU part, OK to replace the part. Once all the sections are back in sync, you can edit the Part again to make any revisions but remember to use Update All when making any changes to keep the sections in sync.