I don't recall reports of such a problem. We'll need more info to attempt to troubleshoot the issue. Start with the prompts on this page: FAQ: What information should I provide when asking a question on this forum? Especially the details on your computer.
Also, please report the following:
- the types of content in your sequence, particularly in segments you're pasting. The source(s) of the content, the codec(s), the duration of copied segments?
- where the content is stored?
- whether either sequence was imported from a third-party program via XML or the like?
- the sequence settings of both sequences?
- what effects & transitions are in use, particularly in the segments you're pasting?
- what is resource usage before and during the copy/paste operation? Is a CPU getting pegged? Does memory usage spike precipitously?
