My Doosan TT1800SY in U/L mode (simultaneous operation) when an M01 is pushed, the first path to reach it stops at M01, the other path freezes mid cut. It's unsafe, non-conducive to efficient production machining, etc.
I called Fanuc tech support, they were unable to find a solution. If anyone knows a parameter change that will allow M01 to be reached on both paths, that would be great to know. Aparently Nakamura runs on a Fanuc 31i-B and optional stop allows both paths to stop at M01 on Nakamura machines. This must be possible but it's an obstacle to getting the machine cutting right now.