On first glance it does appear to be a dramatic insufficient inking error, the back is also affected however so that also agrees potentially with the others opinion. An Insufficient Inking Error can occur with any of the prints. There can be an Insufficient Inking Error occurring during the second print, which is when the front of a note is printed. The seals and serial number were unaffected in some of those cases, this is because they are printed at a later time, in the third print. Others show an error in the first print, when the back of the note is printed. What you show would be an insufficient inking error on both 1st (back) and 2nd (front) prints and 3rd print (seals and serial) unaffected, or something otherwise has affected the ink on both front and some on the reverse that somehow did not affect the ink used for the 3rd print.
You can submit them to PMG
for certification under an applicable grading tier with "error" or the specific error noted under the Variety/Pedigree column on the submission form if its not able to be explained. There is no additional fee for this service.
Edited by datadragon
09/26/2022 4:24 pm