Having an issue with Rockshox Monarch RC3.

When you compress the shock, as it gets to around 30% there is a sort of resistance/Lump for a moment in the travel, then it carries on as normal. Its very noticeable.

I should mention that it is much worse when the compression is on low and barely noticeable when compression is on high?

Anyone experienced this? What could be causing it?

I think i have more questions than answers for you…

If it was around 10% sag then i’d suggest it is to do with the effects of the positive/negative air chamber balancing port being actuated, normally this can also be heard with a slight hiss/squelch sound, 30% sag seems like it could be something else.

Is there noise of any sort during the resistance?

Is there any damage to the main air shaft?

Could possibly be due to a loss of IFP pressure resulting in cavitation until the piston has compressed the oil/started moving the IFP?

Getting firm part way through the travel can also be that the damper has lost oil, but normally i’d have thought this was more obvious when compression is on high?

It has been sitting a while before being put on this bike. I would say the noise is maybe a thud sound. No damage that I can see.
I thought it was an equalisation thing but yeah it happens a bit deeper into the stroke.