do you have them high up in the tank on the highest exposed rock?
if they naturally start to spread up then its different but adding a new
mushroom rock to the highest light isnt the best thing for them as i found this out, they shrivled like a prune. they are very happy now on the bottom rocks and have opened beautifully.
if they eventually grow up towards the top rocks then it wont cause a problem since they adjust themselves, but like i said these were new and werent used to sudden high lights