Yes I have this problem a lot lately here in Texas too, one time about a year ago I dropped 3 packages off inside the post office lobby drop box (within business hours & well before last pickup time). Only one of the packages tracking numbers were scanned by midnight that same night. It really made me mad since this happens frequently, so I went online and filed a complaint and included the tracking numbers that were scanned & the ones that they failed to scan. The postmaster called me the next day, and I explained to him that my job depended on the post office scanning in these packages, and that them neglecting to scan them in was putting my job in jeopardy. He apologized, and recommended that I stand in the long line every day to prevent packages from not being scanned, and I told him I didn't have time to do that. After that day, I noticed that packages were being scanned whenever using the drop box, but now that the corona virus epidemic has hit, things have changed course again, and definitely not for the better! I've had packages get lost left & right it seems, and barely learned about "package intercept", which I'm definitely going to start taking advantage of whenever I have packages that get lost in the postal system!
OH, and regarding Media Mail, I have used that 2 times this year. First time made it to its destination, 2nd time was books I mailed to another address within the same zip code, I watched the tracking as the package drifted off over 200 miles from here, and all the sudden tracking stopped completely. That was over a month ago now, and I eventually wrote that one off, and it still shows last scan was over a month ago. Makes no sense.
