Best guess is the check valve in the submersible pump has failed. Leak in
the bladder could be the cause but after a while there wouldn't be any more
air left. If the problem is the same over and over again then it is the
check valve. If it vgets better after a few cycles then it is the bladder.
If the bladder tank has a vavle on the connection then turn it off and
cycle the pump a few times with 5 minutes wait in between. If problem is
gone then it was the tank, if not gone while tank is off the system then it
is the check valve.

Some things don't make sense - the well being only 80 ft deep with water
level 65 ft down is too close for comfort. Water levels go down with
seasons or drought years. Also pumps draw down the water in the well a foot
to 5 feet. Just seems like well is not deep enough for all likely
conditions. Also, size of bladder is a lot higher than any I have ever
heard of on residential system - 5 to 20 gallons is the norm. Is this a
commercial or other application?