The reason I pointed out the fluid capacity as a concern is that I've seen a similar thing happen with 135 film in stainless tanks. If they're "topped up" if you will, there isn't enough airspace for the liquid to displace and you get uneven development along the edges. I can't remember if it was the long edge or the short edge though. However, this may not apply to you if you're using a different tank setup with some kind of stirring rod which will effectively force the reel around.
And it was something I haven't thought about so a good point indeed. So I checked and there was some space left in the top. But now i have a one more tool in the box when I run into future problems.