First time I thought my fork seals were blown(leaking really bad) they actually just needed to be cleaned properly, although damage to the forks could be the source/cause of the problem.
I've posed several times about this. My forks and seals look just as good as the day I bought the bike, 16,000 miles later.
https://wr250rforum.forumotion.com/t3125-fork-jobsAlso make sure you equalize the air in fork by the bleeder screw on top of your forks before every ride, and you really should do it at the elevation you will be riding in! If this is not done before every ride the pressure in your forks will build up and help push out oil and possibly blow your seal, while also effecting your how suspension behaves.