Hi
There are some strange entries in the Log of my CCRs (v.6.3):
“Discarding packet: MD5 authentication failed
source=x.x.x.x
Invalid sequence number
mine=253202
received=253201”
The session doesn’t get dropped but it looks untrustworthy. 
Btw. This happens only between Mikrotik Routers. No Problem between the CCRs and the Ciscos.
Any ideas?
Hello SwissWISP here is the real answer for that error, this one is a reply to a Mikrotik Support mail:
Hello,
problem may arise if one peer looses connectivity and reestablish adjacency. In this case sequence numbers are not reset and your mentioned error may appear.
Unfortunately there are no fix for this problem in ROS v6, instead I would suggest to use simple authentication untill we finish work on new OSPF code which should fix the problem.