Guys, it could be that the combustion chamber is so much pushed to the limit that it is prone to flameouts during acceleration.
In that case, the only way to stabilize Acycle is to slow down the acceleration.
It could be that the issue that delayed the 100RX production is also the same.
Only time will tell.

Anyway, if this is the case, only a hardware solution is going to cure the problem ( ie a different combustion chamber/ compressor/ diffuser/ NGV/ turbine wheel )