Hi,
Based on the logs you have:
You recieved a OSPF DBD packet from 10.10.10.99 with "seq 0x81db7" & went from Exstart to Full state (MTU of 1436)
Then there is NBR seqmismatch event, a bad one and state changes from Full to Exstart.
Could you check/verify the interface "MTU" is same at both ends?