The joys of essential life saving fluids and electronics
It was beer - that is less aggressive than coffee or god forbid Coca Cola.
I was reminded of the interesting properties of coffee this week by spilling it on top of my Roomba.
As a result, it was finally retired. It survived doing full run per floor (two runs per day) when we were doing an extension (sweeping plaster and concrete dust), it survived cleaning the house with two kids for 8 years after that (+ new battery, brush unit and vacuum bin). It did not survive a double espresso hit in the middle of the top lid (right where the CPU board is).
Coke is even worse. Sugar and industrial strength phosphoric acid solution. I do not recall a single case of successfully salvaging something from a coke spill in the days when I ran a computer repair shop (15+ years ago).
Compared to these two, beer is mostly harmless.
By the way - POE switches are obliged to have quite a bit of short-circuit protection by spec, so the fact that it survived for a while is not surprising.