In the Component Dialog, do you have any clientlib added. Can you see if categories property is added in cq:dialog field. If yes, then kindly find the clientlib and see if the Hide rule is added there.
Dispatcher would cache content and Installation of Service Pack or newer forms package should not affect the content.
I have done Service Pack Upgrade in my project twice in the past and I can confirm that we did not face any issues because of old content cached in Dispatcher.