Since recent versions of BuddyPress require bbPress for forums, we have both installed.
Until a couple of weeks ago I had an old version of the BuddyPress Group Calendar (1.3.1 I think). Now we have version 1.3.6 and I have a problem with the Details input when logged in as an administrator. There appears to be a TinyMCE toolbar at the top of the textarea and this interferes with the input. Switching between visual and text tends to disable the input and trashes any existing input.
I've deactivated a bbPress Enable TinyMCE Visual Tab plugin and switched off the Fancy Editor option in Forums Settings. None of these measures are relieving the issue.
Please test the Calendar together with bbPress to see if you can reproduce the problem. Then help me with resolving the issue.