I’ve got an 11 speed X01 shifter and mech with a KMC chain and SLX 11-46 cassette.
A few months ago, I had an issue half way round CyB where it refused to drop out of first.
Clicked the trigger, nothing, like the mech had just seized. Paddles moved fine though.
A lot of shifting up and down later and it eventually freed itself. It was a very wet day and I was tired, so the bike went back in the car afterwards.
It’s done this a couple of times since, so I changed the inner and outer yesterday, and lubed the shifter internals.
Whilst setting up the tension, it did it again in the stand. Really odd. Gave the mech a push by hand and it dropped down no bother.
So, what’s up? No problems up until now, been running sweet as for a good year. No knocks, hanger is straight (checked with a tool)
Fine on the rest of the block, shifts beautifully.
I’ve left it drenched in oil, but I’m kind of at a loss.

How old is it? My XX1 mech is doing this and it’s about 7 years old. I’ve taken it apart (it’s not difficult) and even increased the tension on the spring a bit and cleaned it and oiled it but it seems the little plastic washers used on the pivots are worn, the bushes are worn and it’s all just sticky. It’s got bad enough that I think the only option is to replace it.

Is the mech too far away from 1st gear?
-Dropout is very thick or isn’t according to the sram design guidelines?
-Using a non boost wheel in a boost frame (similar to above)

If none of the above, jockey wheels goosed?

Does the mech make an attempt to move when the shifter paddle is clicked?