Well, I've seen people with IBD bleed from taking hard fiber in the past, though not with that one. But, yes its possible.
But I bet you are just having a (hopefully brief!) Flare. Mine often happen with stunning speed..
I'm just a supplements sales clerk who is a Crohnnie, but I never use or recommend psyllium for IBD'ers, you might look into acacia as an alternative. Psyllium is known for plugging (slowing or temporally stopping) in the intestines, even for non IBD'er's and causes me bloating. Acacia does not expand after you consume it. Everybody has issues with psyllium if they do not get enough water. If their magnesium is to low, the water is not transported to the intestines. You might think about buying some 200 mg Magnesium , in case the 450mg is to strong for the long run, It helps keep things moving, but to much can cause D. For times you want more, just take two. Just my thoughts...