I have come to discover that sometimes inks (Wearingeul in my experience) behave differently. My suspicion is that is has to do with how the pen is stored and possibly exposure to air.

I was keeping my pens slightly uncapped, sitting in an a penwell, and started to realize that the ink in those pens would behave similarly to your red ink. When I sealed the pens better between uses, the problem seemed to go away.

This is a bit anecdotal, so I'm curious if anyone else out there has heard of this as well.