Canada #596 - Op4 Example With No Migration

Still plugging away at this plate block collection and along comes three of these. They are Scott #596, vertical ribbed, from Plate 1. Under UV light, the tagging does not really show up like it's fluorescent brethren but the tagging bars are quite visible both with the naked eye and with UV but are quite faint so it wouldn't classify as untagged. At the same time, when I remove the UV, I don't seem to notice any after-glow which I thought was supposed to occur?

My best judgement is that the stamps themselves are LF front and DF back. All of this is fine and dandy and would make it 596xii according to Scott if it is, indeed, W2B.

However! The catalog states that these are only available in corner blocks of 4 with no plate description. I have 3 plate blocks with inscriptions.

Am I incorrect in this deduction somewhere along the line? Anyone know if this is a new or recognized variety?

I've attached a photo of them.

Thanks in advance!