Someone completely Misidentified this postmark and made the HUGE mistake of marking this historic cover in ball point pen! Certain things have absolutely NO PLACE in the world of Philately. One is ball point pen, another is tape! So many times I get a cover in the mail completely mummified in tape that requires surgical precision to remove without damaging the cover.
With this cover Someone who clearly knows absolutely NOTHING about stamps decided this cover was dated 1918 and even worse wrote it in the center of the plug in ball point pen!
I did a LOT of research on removing "permanent " markings from historic documents. I found this method being used by a conservator of historic documents. I've used this method many times and it is definitely the least damaging and most effective.