My crystallinum is crisping up very fast! The 2nd set of pictures is only 2 weeks ago. Does anyone know what could be the cause? -It's just in a living room environment at 30-60% humidity. -It sits on a shelf next to a south facing window so it gets a lot of light but no direct sun until later in the evening. - i fertilise it on every watering, as it says I should on the bottle but at ~half strength -Can't find any signs of pests or anything

It's 3 plants in one pot and all of them seem to be bothered with something. The smallest one just pushed out a new leaf but now its one older leaf died of and its not opening the old one yet. The middle sized one (smaller REALLY crispy leaf in pic) made new growth ~2months ago which died immediately all the way back to the base so it's now trying to activate a new growth point but it also seems stuck. The biggest plant just made a new leaf (only intact leaf on pic) and that seemed fine but is now also getting "rusty" looking spots. It just made a new leaf but half of the leaf was dried up when it came out the base of the other leaf (don't know the name for this😅) and because of that it had trouble unferling and the dry part just crisped off. So yeah, its clearly not thriving! I reaaally want this guy to be happy but have no clue where to start! Any help would be greatly appreciated! :)