My fork recently developed a problem at a race weekend where it was bottoming out before reaching maximum travel.
Turns out air was trapped in the lowers, which I fixed with a cable tie between the wiper seals and the stanchion.

Having fixed this just before the race, the damper bladder then burst halfway through stage 1 – no more damping 🙄

I’ve bought a new charger damper and fitted it yesterday, along with new lowers seals and an oil change. Damper works fine, everything back together properly.

Went riding today, and the forks were feeling increasingly firm as I rode, until they almost felt locked out at 70psi. I assumed it was air in the lowers again, so I removed the foot-nuts, and sure enough, a load of air came out.

I then depressed the damper and air-spring all the way in before tightening the foot-nuts back on to try and ensure there would be no air trapped in the lowers.

Then I pumped the forks up and they were sucked down to 10% sag with no weight on the bike.

I then removed all the air and tried to pull the lowers all the way out to equalize them. No hope.

Decided to take the air-spring out, not really knowing what I hoped to find. It’s covered in grease, but looks in good condition to be honest!

I can’t get to the bottom of it, any ideas?! Bloody nightmare!

Sorry for the essay

Is there to much grease blocking the positive and negative chamber notch? with the inards removed you should see a machined notch inside the leg. This let’s the chambers equalise when moving through travel. If it’s blocked with grease it won’t function.

Ahhh that’s probably it then, there seems to be copious amounts of grease all over the air spring.
Will take a look tomorrow morning.

Despite using the cable-tie between the wiper and the stanchion to release the trapped air the actual fault is still unresolved. The reason that your lower leg had unwanted air trapped there is due air migrating from your air assembly inside the left stanchion.
The reason air is leaking from your air assembly and into the lower is hopefully just a worn or damaged air seal but you also need to check for any slight imperfections/scratches on the air rod itself.
If there are any small marks on the air rod it will bleed a small amount of air into the lowers every time the seal at the base of the stanchion passed over the scratch on the air rod.
New o-rings on the negative base plate of the air assembly and a scratch free air shaft will get your air issues resolved.
Don’t get too worried about if you have too much or too little grease on the air seals and blocking the port etc as this is not really as big a deal as people make out. Many people pull it all apart and only pay attention the grease/bleed port which is not really the issue. They then re-assemble and report to the world that they’ve cured their fork when actually nothing has changed and fork will slowly continue to bleed air into the lower leg. The second you remove the lower leg on a fork with air trapped the in the lowers its going to feel ‘repaired’ as soon as you re-fit the and pump the fork up, as you’ve just released all the trapped air.
Sadly on forums the amount of incorrect advice often overshadows the factual advice. At the end of the day my best advice for any suspension issues and advice and call the UK distributor (Mojo for Fox, Fisher for Rockshox) They will give you the correct info and save you a lot of time and hassle.
My advice comes from 10 years of experience of repairs on forks for various companies here and abroad. I’m not saying I’m the man but I do know a thing or two! 😉