Unusual growth on rhodactis mushroom

[Moort82]

Probably won't help but i'm trying to id a growth without a pic. Its on a friends rhodactis mushrooms, which i've only seen pictures of. They look huge and are said to be 8" across or so when expanded. The growths in question only seem to effect 1 of the colony.
The base colour of the mushies is green but these growths are a bluey grey much like you'd expect the underside to be. They resemble large irregular bubbles and have been there for a long time now. My first thought was that they were a reaction to damage but there hasn't been any apparent damage and they have always been there. So open to suggestions, the only thing we can come up with is a possible means of reproduction?

Trying to get a picture of these sent over to help but until that arrives, would be greatfull for any ideas.

TIA

 

[organism]

I've seen it happen on a few different rhodactis and even yumas sometimes, it's just some weird reaction to light that makes them do that sometimes. It either goes away over time or just stays on there, nothing to worry about though.