Strange mismatch involving serial number under UV

This is a weird one!

I was going through some images to upload to the catalogue and I hit a snag when I checked the UV images of this note.

Firstly this is the watermark area with the serial number as seen under backlight:

Ends in 461, no question about it!

The obverse UV agrees:

But here is the reverse UV, it ends in 462:

I know what you are thinking, and I thought the same thing: I must have photographed two different notes when doing the UV. The only problem is, this is the only note of this type that I have. I did actually photograph it again and I got the same result.

Here are the two photos under UV again, this time with the reverse horizontally flipped:

You can tell this is the same note because there is continuity of the fibres.

So, how did this happen?

All I can guess is that the 462 note rubbed onto this 461 note (the obverse of 462 rubbing on the reverse of 461) when they were in the bundle. But if that is the case why isn't the 462 impression on my note fluorescing green?

That is very interesting.

I would suggest that it is an offset transfer error involving UV active ink. If so, a most interesting error note.

I had a look at some other bearer cheques: this phenomenon is on all of them!

Sloppy printing perhaps?

I would like to know if that is imprints or transfer. I can't make head or tail of it so far.