MySql replication failed with error 1236 data position > file size with relay-bin file not increasing
To avoid the problem in the future, turn on sync_binlog.

What is happening is that the replication stream had not yet gotten to the Slave when the Master shutdown.  The offset into the binlog had been bumped up, but the data was not on the Slave.

After coming up, move to the next binlog and set the position to 0 (or 4, either one works).