OP is there any official PPB / City / State insignia on the other side of the sheet?

That looks a lot like something a random busy body would print out and stick under wipers just to feel important.

I missed the vote that gave Portland/ppb/multnoco the funding to print out thousands of "warning" pamphlets, nor the equipment to double fold such a printout ( nor the extra staffing to folding those things if their printer or printing company isn't folding it for them ), nor have I ever heard of or seen anyone in Portland giving any "warnings" for anything parking related - how else are they going to pay for all the pothole repairs if they don't issue actual tickets ?