I see this problem in Circuit S3 demo by Analogue:
it clears interrupts, it enters protected mode, it executes rep movsb.
Before the mov finishes, an int 08 occurs, which is serviced.
This causes flags/cs/eip to be placed on the stack which overwrites (due to poor coding by Simm) the previous return address, and the demo won't run. I don't understand how why int 08 runs with interrupts cleared.