Has Anyone Seen This R155 Overprint Inking Anomaly Before?

I *KNOW* I've seen an image of this inking anomaly before (different stamp), but I'll be darned if I can track it down now and it's faded from the depths of my memory.

It's like an oversized "I" in "I.R.".

This is going to bug me...

My brother saw this and thinks it to be either a raised spacer, or piece of "wooden furniture" used to tighten the type in the chase.

I was under the impression (no pun intended) that these I. R. overprints were created on a Linotype machine as a continuous slug, without individual en or em spaces between loose type. So I don't think it is from a raised spacer.

The spurious ink could have come from a raised piece of furniture though. Or maybe something got temporarily stuck on the non-raised area of the form, and it then became a printing surface.

It's weird that it is at an angle though...

Jim