Thanks i will remove the mushroom, the leather seems to look like it’s got bits falling off any way to know when i should give up as i don’t want it to release toxins into my tank when dying?I do agree to move that mushroom. If you can, most likely attached to the rock and so is the leather. Good luck, but one of them has to be moved. You could cut that mushroom off with a razor. Temporary move because the foot will regrow a new one. But it might tell you if it is actually bothering it.
Run carbon to soak up the toxic warfare going on.
Also, sometimes leathers just expel the water out and get floppy from time to time.