[microtonal]

Yes, this happens to people all the time. The seals that keep water out degrade over time. New phones are generally ok, but heat, dirt, detergent/salt in water, etc. wear them down until they are not water resistant anymore.

This is also why almost none of the manufacturers will fix the device under warranty when there is water damage, despite the IP rating.

Even Apple themselvers recommend against submerging and iPhone in water:

To prevent liquid damage, avoid: [...] Intentionally submerging your iPhone in water

https://support.apple.com/en-us/108039

The water resistance in these phones exist so that the phone hopefully survives when they get wet accidentally (heavy rain, pool drop, etc.). Not to shower with the phone, cleaning it by putting it under the tap, or doing underwater photography. Usually, it survives, until the seals fail.