I have a first generation iPhone SE. I dropped it into sea water for maybe about 10 seconds yesterday.
It appears to work fine when there is power left in the battery. The issue is the charging. If I put in the cord and then restart it, or put in the cord while it is off and then it turn it on, the phone charges (possibly more slowly, but I'm not sure) basically as normal. But if I put in the cord while the phone is already on, it does not show the charging indicator (or if the cord was on from boot, taking it out stops the charging and putting it back in does not resume it).
What could be the issue? I assume it can't be purely hardware because of the relation to booting. Any suggestions on how to get it to charge without needing to boot it afresh each time?