Application Stops Responding when nesting video clips
PP stops responding entirely after clicking the "okay" to nest video clips together. Tried unlinking from the audio (suggested by another user) and had the same result. No issues nesting graphics/other elements, the issue only applies to videos with and without effects applied. Tried uninstalling/reinstalling app, using the 2 previous versions of PP, and still got the same result. This is a new issue and have never had a problem nesting clips before.

-
Jason S (Adobe) commented
Hi, Gabby. Sorry about that. We haven't seen this locally so the easiest way to debug this would be if you could capture what the app is doing directly. On Windows you can create a dump file using the instructions at the first link below; on MacOS you can create something similar using the instructions at the second link. Once you have that please e-mail me at jschroed@adobe.com with the file / link to the file (the .dmp files on Windows are pretty big, so you'll want to upload it somewhere) and I'll take a look. Thanks!
https://helpx.adobe.com/lt/photoshop/kb/how-to-get-a-process-sample-or-spindump.html