I can see how a bent axle could cause leaking.. imagining a little runout that widens the ID of the inner axle seal. But only way i'd know to check it would be to pull it out, then put the thing up on V blocks and measure the runout. IIRC, there's a big surface place up where 60wag works where you could actually measure a long side.
But then again, you're not full time 4 so your front axles don't really spin that much, right? Like, maybe they've spun 500 miles since you replaced the seals at the 04WBPP? So I dunno.. they'd have to be really bent to cause a leak so quick. Probably more attributable to the oil & grease mixing because of your grooves. I just bought new axles for the same reason, and will be going in there again fairly soon. HTH..
82 fj40, 99 uzj100, 06 gx470
97 DR650, 05 525EXC, 01 XT225, 89 TW200, 09 TTR125, 07 TTR90, 07 CRF50