I'm decently comfortable with Fanuc's ladder (Thanks in part to this wonderful community) But I've stumbled on a small annoyance that challenges my understanding of how M-codes are supposed to be handled by the CNC and PMC

On our new Star SB20R Lathes, there is a rung (picture attached) with a simple Holding circuit that looks to be started by M183M (R42.7)
But when i MDI M183 The machine just halts and doesn't clear the block. It never stops or alarms out due to missing FIN, cycle start lamp just stays on and the Coil R1740.1 is never activated

M183 From head2 (R142.7) makes the machine behave exactly the same way and This R adress isn't present in the ladder at all.

The relevant Decode blocks handles up to M200 for both paths and adjacent codes work as expected Both M182 (R42.6) and M184 (R43.0) Alarms out due to missing FIN. And after i add them to the MFIN net the block is cleared as per usual.

The only other occurrence of R42.7 is in said MFIN net And R1740.1 is only to be found in the net in the picture.

is There something in the CNC's software that can prohibit certain M-codes fron being sent to the PMC?

Context:
I've installed Air blow valves in a bunch of our lathes to clean both parts and tools from swarf and used M-codes 180-185 since they were free on all the machines i checked. On these machines I was going to close off this seemingly useless Rung with a Keep relay and repurpose M183

Just for Operator comfort i'd like all machines to use the same commands. I can and probably will have to extend/create new DECB blocks to get what i want. But that's kind of a hassle and people will have to relearn codes and alter old programs.

Biggest thing though, is probably that i need to know wtf is happening.

TIA for Anything. I'm losing sleep over this little thing haha