Rapid flips when selecting RTL

I was checking the different flight modes and on one occasion I switched to RTL and the quad flipped a few times. I quickly went back to loiter and it recovered thankfully. I tried RTL a few more times after this and all seemed OK. Looking at the logs I see a Roll at around 5640 with no RollIn at the time that RTL was selected. This goes back to normal when Loiter returns. I can’t see any reason for this to happen. Hdop looks OK no errors etc. Can anyone see anything I’ve overlooked?

I think this should be in the arducopter section

I’m looking for help diagnosing the problem from the logs, so isn’t this the correct place?

This log file is corrupt, how did you download it?

This turned out to be a motor or esc - thanks to your help on another post. I have re-attached the log as it opens fine for me in mission planner. If it’s OK would love to know if you think this also points to the front left motor?