Inflating Sheath

[Cattleya17]

Hey guys whats up?? My cattleya i posted about earlier asking if the buds will survive without thier sheath(btw is still going strong and developing normaly) well one of the other sheaths that also showed signs of development has turned brown and has dried up. i know this is normal for Fall types to bloom from dried sheaths and in not going to rip it this time! but now the sheath is inflating! like a balloon! i squeezed it and it pushed back like it had gas! so strange. so i was wondering if that is normal???