That's really odd, I had my only real success with coco in auto pots. And I've seen people have issues with it though in auto pots. The problem I think is the placement od so called "drainage material" in the bottom. this is a myth. the laws of hydraulics says, the interface between dissimilar materials will resist the flow of water until over come by gravity. Which tells you its even more of a problem when trying to wick against gravity! What happens is that the wicking of water still occurs but is greatly reduced, to the point that the surface of the coco drys out too much. In the process, it leaves salts behind... i never used "drainage material" in the bottom of any of my pots, it never made sense to me and I find I was right. With reasonable PPMs, coco in auto pots works very well. Didn't Hansbrick run coco?
ive been using it since 2016 and i find i only ever have issues with autopot bottom-fed plants with top-fed like my airport i find as long as you always feed to run off its pretty easy to keep your plants happy but even though I've grown in coco in every size pot or container solo cups 2 litre bottles but try not to overfeed your plants but @Mañ'O'Green knows id say more than most of us regarding it