Having more than one library of different types with the same urls stops rendering the items and results in exception (FP)
Pages
Multilingual: delete translation of a page that has child page, but not in the current language is possible from Actions->Delete and not from page edit screen of this page (FP)
Users
LastLoginDate of front-end users is not updated (FP)
Frontend users are not redirected to the url specified in the ReturnUrl query string parameter after successful login (FP)
Site Sync
Syncing pages with disabled additional url to an existing page (FP)
Other
Configuration option for sts_logout query string passed automatically. It allows to sign out from the STS instead of the relying party. The setting can be found in Administration -> Settings -> Advanced -> Security -> StsSignout (FP)