I've added recently some new projects with accents in their names, and while I tried to edit members, or edit their picture I got this error.
The thing in common which the projects share is that all of them had some special chars in their name, like accented characters (á, é, ő), a space, or points.
When I renamed them, I stopped getting this error.
Unhandled Exception ("AphrontDuplicateKeyQueryException")
#1062: Duplicate entry 'kaposvar.amienk.hu-4' for key 'token'
Fatal error: Uncaught exception 'Exception' with message 'Process exited with an open transaction! The transaction will be implicitly rolled back. Calls to openTransaction() must always be paired with a call to saveTransaction() or killTransaction().' in /srv/phabricator/libphutil/src/aphront/storage/connection/AphrontDatabaseTransactionState.php:69 Stack trace: #0 [internal function]: AphrontDatabaseTransactionState->__destruct() #1 {main} thrown in /srv/phabricator/libphutil/src/aphront/storage/connection/AphrontDatabaseTransactionState.php on line 69