HCL has released IF1 for Domino 12.0.1, which contains a bug fix that causes the server to crash.
The problem occurs during fixup when the Fixup operation on databases with a very high number of NLOs causes a high number of locks which effects performance. Domino Server is showing multiple database locks on daoscat.nsf. This can cause the server to hang. The server stops responding and has to be restarted. In some rare cases the Domino server is crashing with error – “PANIC: semaphore invalid or not allocated”.
The problem occurs in version 12.0.0. The IF has not yet been released, however you can use HCL Support to obtain the fix pack.