Anyone had any problems with their RB Fire11?

I have ran the motor in and had a few heats, during the main it had a two flame outs but fired right up again no trouble.

When the final was over i went to fire it up again just to run some after run through it, but for some reason it just keeps getting stuck at tdc.

I have stripped the motor down, everything looks good, no bent rod, bad bearings, nothing.

So I bolted it all back up, pre heated it and straight away with no fuel, motor warm, it got stuck again at tdc.

Checked starter box motors and battery,(running twin 775 motors in starter box) and also tried spare starter box but same issue.

Anyone got any ideas on what is going on here.

Before the heats, finals it started up fine.

Any ideas would be greatly appreciated.
Cheers.