Elimination communication regression

Anyone else experienced this: I've been offering a potty to my LO since they were 4 months old with limited success. Then around 6-8 months it really seemed to stick, they always went to poo in the potty instead of the nappy, they had a wee on their potty pretty instantly after naps and before their bath.

Around 8/9 months they just seemed to completely regress. We are now lucky to get a wee or two in the potty. They never poo in it, will actively scream until we take them off the potty then poo about a minute later. They're now coming on 11 months and still isn't showing signs of returning to using the potty as we were. Their cues are much more subtle now too.

Wondering if anyone experienced the same and what you may have done about it to help get back on track. He wears reusables mostly but recently in the last month we have been on holiday a lot and with family so used disposables more, I know these make being soiled a bit more comfortable and wonder if that hasn't helped.

Thanks