I’ve got an odd problem of the chain randomly skipping when on the smallest cassette sprocket.
Have a new cassette, new chain and new chainrings. Mech is adjusted well for shifting and the B-screw adjustment
Doesn’t always skip when applying full power, but more on medium or as soon as I back-off from full power.
Only other thing I can think of it a stiff chain link. But there are no obvious ones I can see, haven’t got around to manually checking them all yet.

Any other ideas?

Chain too long?

Check the jockey wheels on the mech

Your limit stop might be set very slightly too far inward for the smallest cog?

Cable routing? I had a similar problem and comparing the cable routing with the Shimano instructions found I had it the wrong way round. Quite a few internet forums suggested this was the problem so I switched it over. A combination of that, and going SS, seems to have cured it.

derailleur hanger alignment? Might have to take it lbs to check it though

Hey Matt,
I had the same problem in August. New jockey wheels cured it. Check if yours are looking a little pointy.

BTW, it didn’t seem to be a problem on Wednesday night, or did I just miss it?

Had a very similar problem last year – would skip under power and on bumpy trails. Turned out when I had replaced the cable I had cut the outer to short under the BB thus when rear suspension compressed it tightened the cable.

Worth a check (if its a full susser)

Bent mech hanger… only needs a very small bend / twist to have an effect on shifting.