You said that you touched up with the last 2" in the can. I think the material that caused the shine was in the bottom of the can, and hadn't been adequately mixed in to begin with.
Two months ago we had our bedroom painted, and in some areas there was a lack of coverage, so when I pointed it out, the painters went over it with the last little bit of paint, scraping the sides and bottom of the can.
When it dried, this paint was visibly lighter than the paint applied earlier! (This was Benjamin Moore matte paint, mid-grade. Good paint.)
Another painter told us that issue was due to a white pigment in the bottom of the can, that was inadequately mixed into the paint before it was applied to the wall.
I bought more paint, and told the guy who mixed it about the problem with the earlier batch. He spent more time mixing the new batch, and the color problem didn't happen again, although I removed little lumps and painted over places on all the walls.
We learned lessons:
1--Be very careful that the paint on the bottom really gets mixed in.
2--Cut-rate painters don't do all the needed prep work, like getting little pieces of sponge and old "pimples" knocked off the walls before they start painting. But you can do it. It would have been much easier to do it before the paint went on, and avoided the repair work I did.
3--If your painter is confident he won't spill a drop and doesn't want to cover the WHOLE floor, SEE THAT IT GETS PROTECTED. Especially if you hired a cut-rate painter. I spent hours cleaning the tiny drops of paint, and smudges of paint that got under our feet and then on the carpet. Our painter knocked over a loaded paint tray, on brand new carpeting, too, but did a good job cleaning up 99% of it, with water and a water vacuum cleaner. Better that the carpet had been fully protected to begin with. For the next room, we covered the whole floor before they arrived.