I made some changes last night and the only problem I had was it wiped out all the buttons on my Watch TV activity - no idea why, but it is my simplist activity so it wasn't a huge deal to redo it.

The other thing that seems to happen the odd time is it will remove my antenna rotator from activities at random when I update - I just have to re-add it to the activity (and the buttons automatically repopulate the way I had them).

A couple odd quirks there, but neither is a huge deal for me.