Samba 4 beta8 PANIC: internal error

[steve]

Hi

2 replicating DC's updated an hour ago.

DC1 starts fine but as soon as DC2 is started:
INTERNAL ERROR: Signal 11 in pid 25065 (4.0.0beta8-GIT-11a5646)
Please read the Trouble-Shooting section of the Samba HOWTO
PANIC: internal error
Terminating connection - 'NT_STATUS_CONNECTION_DISCONNECTED'
single_terminate: reason[NT_STATUS_CONNECTION_DISCONNECTED]
Bad talloc magic value - unknown value
PANIC: Bad talloc magic value - unknown value

I ran
  samba-tool dbcheck --cross-ncs --fix
on Both DC's without errors.

Any ideas where to look next?

Cheers,
Steve