He LOVES to swim in the ocean - in fact he'll happily jump in on his own when we are swimming, swim over to us - even if it's 20 meters or so, turn out swim back - and then jump in again etc etc.
But - there's an odd sore on both of his ears that has been recurring over the last few years and no one seems to know what it is - so I thought I'd ask for some collective wisdom.
here's Max swimming with Mum

Here's the RIGHT EAR - with the sore dried over (This is the sore from last year) - as soon as he's out of the ocean for 10-15 days it dries up and never reopens (until the following year

Here's the LEFT EAR - with the clearly visible oozing sore

He doesn't appear to be in pain - but it's just so strange. Local vet seems to have no idea - just seems so odd that it always recurs in the same place and only after he swims. I guess it's possible he vigorously shakes the ear flap apart - but it seems very strange - why would it not heal up fully over 9 months?
Anyone got any thoughts? Mum (and Max) would both appreciate it.
Here's an older video of me taking Max into the outdoor shower - https://www.instagram.com/p/BWioQv1ANDu/
Thanks for the help
Nick