Hi pressure spiking after pressure switch shutoff with CSV1a

[bpitas]

My wife noticed some water on the basement floor, and I traced it back to water dripping out of the 3rd fitting on the CSV1a, the horizontal outlet across from where my pressure gauge and switch are attached..  I took a video of what's happening https://youtube.com/shorts/oZ6xzAZ8Kw4?feature=share- basically when the demand for water is over, the pressure shoots up and you can hear the pressure switch turn off at 60psi, but the pressure gauge keeps increasing quickly until it hits 85psi.  The water at the taps doesn't look like it's coming out at 85psi when you first open the faucet, so I don't think it's really running that high, but given the leak on the 3rd outlet, something's not right.  What could the problem be?  I have a plumber coming over, because I suspect it might be a waterlogged pressure tank, but was wondering if anyone had seen this behavior before so I can tell the plumber where to look for the issue.
Thanks in advance!

[bpitas]

Posting an answer to my own question in case someone else benefits - basically the small pressure tank, even though only 4 years old, had a bad bladder and needed to be replaced.  Apparently the pressure tank absorbs the spike of pressure once the demand for water is over, but when the pressure tank is waterlogged, all of that pressure goes directly into the system, resulting in high pressures.  The plumber replaced my pressure tank and pressure relief valve and now everything is back to normal!

[Cary Austin]

Sorry for the delay and your problem.  Glad you got it working.  Yes the air in the tank absorbs the expansion.  With a water logged tank the expansion continues until the relief valve pops off.  Those little tanks should last longer than that, but they have a 5-7 year warranty.