There are diff ways solenoids work. Some simply trips the sear to release the ram/bolt on high pressure blow back markers, and high ends mainly use electropneumatic solenoids that pretty much just directs the air that is used to cycle the marker's ram and/or bolt forwards and backwards.
As you have read, alot of people complain of leaks in solenoids, and this is a direct result of overpressurization. Electropneumatic solenoids use very small orings called buna orings, and they are very fragile, and they arent meant to withstand any more pressure than the manufactorers limit. Some solenoids can only withstand up to 100psi, and some others just over 200psi. But most if not all use a bleed valve that will leak out extra air pressure when overpressurize occurs, but blown buna orings happen all the time anyways.
Hope this helped, but you would be surprised how much more there is to learn.