I would not hesitate to shoot those, when shot-shells absorb a little moisture they get less powerful not more.
I dropped one of those in a steam during the hunting season and the water was too deep for me to retrieve it,
the following summer was dry and the water level down I picked up the shell wiped it off and out of curiosity
stuck it in my shotgun. I was expecting a dud but it went off with apparently full power!
If you decide to try just be certain the slug cleared the barrel before you try another