Try possibly deleting chainstate,database,blocks and all files except .conf and wallet?
Could be the chainstate file.
Also I know you tried but ensure you sync from 0 with no banlist.dat present?
Could be an old blockindex stored somewhere.
Ive been able to get all mine up on the new version so something must be grabbing a blockheader from an old online node.
Ensure on your LAN all nodes are updated first also?