Difficulty editing MKV parts

Hello everyone on board, I’m a new user of VEAI, I’m German (I can only communicate using Google Translate, please understand). I have a batch processing of mkv parts that I previously cut with MKVToolnix (because I read that there is no save function in VEAI. So I work with parts.
When loading these sections, it takes ages for the section to be recognized. Can this be related to the time stamps? In addition, the editing is not recorded. Only after I have started VEAI a second time does VEAI start processing.
I read here in the threads that it is better to block VEAI on the internet. Is this statement correct?
Thank you for answering…