Hi Bill,
The fact that your issues are specific to Communities & Collections makes me wonder if you've somehow customized the Community & Collection forms? If so, my guess would be that you may have customizations that are no longer valid/working for DSpace 7.6.2 (and you may want to revert them, see if that fixes the bugs, and try them again).
Hopefully if someone else hits this issue, they will also report it. But, right now, I cannot find a way to reproduce this in 7.6.2, so I suspect it's something on your end (either custom code, or some issue in your upgrade process).
Tim