I think you are correct you. It would shock the shit out of them. Thats the beutiful thing about working with smaller pots and transplanting. It like a reset button, but those pots are large in relation to plant size to do much good.
I doubt it was a burn of any kind. It is just showing deficency due to poor root health.
Its just robbing peter to pay paul. Peter is the leaves, paul is the overall health of the plant to survive and start to thrive. ya dig?
IMO clay pellets are better choice than coco. Less chance for salt buildup than coco. Both have diffrent water retention properties based on how it is proccessed and size alone. So chunks of coco in soil would get diffrent results than the fine ground stuff that you have. Does that make sense? However I still think you got to pick a side like democrat or republican. Picking a side; hydro or soil will save you alot of complications being new. I have seen some skunk magazine articals refering to I think "artificial reef, quantum living organic???" It was a 5 part series. It was using Coco, soil, worm castings, oyster shells (can be sub for domolite) and tons of other great organic stuff in the mix. The backbone was based on coco and soil (similar to what your using now). It was some advanced reading. Your % of mix has to be correct. I wouldnt reccomend it for a beginner cuz it had so much info it could make your head spin, but the pics of those bad ass ladies still is engrained in my head.