[RICE RACING]

I have built hundreds of engines since the very early 1990's and never had one seize or lock up, have seen ones that have though and all have been oil system failure related.

Oil pick up
No engine oil (oil line leaks, broken sump)
Oil pump drive failure (small key not installed ! or aligned properly)

Check the pick up when you take the sump off, check the oil pump drive, check the thermal pellet in the front of the E shaft, check the oil galleries in the E shaft (as I saw one that was blocked! and caused a front rotor to not get any oil and seize hard on the shaft. Look at everything in the oil system (look for oil in sump lol) and you will find the cause of why it "locked up".

lack of oil supply (flow and pressure) will be the only statistically most probable thing that will lock up a rotary, that and snapping the E shaft in half lol.