today about 3/4 of the way round llandegla, my chain started going horrendously wrong – whenever i was on the granny ring and stood up and put some power down, the chain kept getting stuck between the granny ring and the frame, and it jammed.
Here:

Most of the times this happened, it caused the inner link to bend, and eventually i had replaced so much of the chain with power links that it was too short to go on the big ring, which made it even more likely to happen. What a mare. I think the fact one of the links was bent only made it happen more, but why it happened the first time is a mystery. Any ideas?
I'm not doing anything weird like having an odd set up or anything. Just got standard double-and-bash saint crankset, and yes it has got the correct BB spacers, two on the drive side one on the left.

after gisburn last weekend it did develop a few orange spots, but was still moving fine, so oiled it and thought nothing more of it, and it was fine a penmachno this morning. I'm tempted to think that the water at penmachno washed all the oil off and then it dried off as it was on the rack batting along the A5, meaning it was without oil OR water, and this dryness meant the links were leaving the inner ring too late, i.e. too high. It was on the black run and i had just landed a jump not too brilliantly when it started occurring, but stayed on – so can't have been that bad, certainly nothing else took a hit, so can't see how that could muller just the chain.
Did the chain checker on the chain when i got home and it was on 0.75% but not yet 1%.

Reassurances that dry unlubricated chain is the cause, or clues as to what else is to blame, much appreciated…

Welcome to chainsuck.

Had the same last weekend at Lee Q bonj – there'll be some familiar sounding descriptions in this thread (esp. bassspine's post, #2)

I got my granny ring changed, & there wasn't a hell of a lot of wear on it.

I'm amazed how much difference a few drops of oil on the chain can make. My commuter often gets neglected and the gear changes go from crunchy and clicky to smooth and crisp after a bit of oil.

Had the same last weekend at Lee Q bonj – there'll be some familiar sounding descriptions in this thread.

I got my granny ring changed, & there wasn't a hell of a lot of wear on it.
ah, thanks – good link.

I did have a look at the granny ring's teeth and some of them are noticeably worn, so maybe it was a combination of worn teeth and slightly worn/badly-lubed chain.

so maybe it was a combination of worn teeth and slightly worn/badly-lubed chain.

Add into that fine gritty water, or otherwise shitty conditions..

yeah. I think i may opt for a steel chainring now. not that it'll prevent it ever happening again, but should take a lot longer to wear.