Fix reply alerts could fail for collaborators depending on if they did not have the "View threads by others" permission. Take #3, should really fix it this time
Fix user-reportable error may not always be returned when using thread collaboration
Fix redundant queries could occur when viewing a forum when "Thread list: use separate query to fetch collaborative thread user information" option was set
Fix edge cases where permission checks may not restore the collaborator's permissions as expected if they are in a non-valid user state
Improve handling where a collaborator could have permissions removed when the thread starter was banned or had significant permissions revoked, most noticeable with "always collaborate" permission