Same Pick Number With Different Signatures? Not Possible

[Numisnote]

Hi PMG

Please explain to me how there could be two different signatures as Pick 5a?

Please look at the photos, the first two photos show the note in question, the 3rd and 4th photos show The same note PMG graded as 5a and 5b which are correct according to websites on the internet, what is the true pick number of the first photo?
It can’t be 5a with different signatures, what pick number is it? Thank you
 

[Jennifer F.]

Good afternoon,

I checked with our research manager and he advised that it looks like Pick changed their numbering at some point.  The current numbering is as follows:

If you have something that was labeled under their old numbering system, we can reholder it for you and update the Pick information for a $5 charge.

Thanks!