Board Thread:General Discussion/@comment-13047776-20170324164205/@comment-31420441-20170326173251

No, it doesn't happen in the Ben 10,000 timeline. So far as the end of Omniverse, the Ben 10,000 timeline from Ben 10 is the same as the main timeline (with minor changes and retcons).

The episode in not a part of the main timeline. It was also never stated to be part of Ben 10,000 timeline. Assuming that is just fan theory.

Also note, that during the original series, the Ben 10,000 timeline wasn't a timeline. It was the future. While Goodbye and Good Riddance was a decidedly different timeline.