Keep an eye out for water in fuel

[Mattblack]

Can a faulty fuel vent cause a problem like this?

[repspec]

yep!
If its leaking/broken, it can get water down it while your washing the boat, out side, wave over the side etc.
Deck filler oring's can break up over time and can leak/not seal properly.

[frozenpod]

the other thing to consider is all the recent rain we have had.
Is the boat under cover? If not, id be checking all you deck fill points (including breathers)

At the same time, keep an eye on when you wash the boat, if you hose over breathers/deck fill points.
.

Yes undercover.