Some time ago LEGO updated the packaging of the baseplates. At first people thought baseplates were going to be discontinued, as they were out of stock in most places. Because of this LEGO made a statement that baseplates would soon return, the only difference being the packaging. I bought dozen of baseplates in the past, as I build a lot of moc's, and recently I was in need of some more. So I went over to the shop and bought some new baseplates. However, after I removed them from their packaging I noticed these baseplates were different.
First I thought I bought fakes or production error's, but I went over to the LEGO store and bought some more that show the same difference. I don't mind if they update or make change to their products, however a problem has occurred. I will make it more clear with some picture and a video I made. It's been a while since I bought some baseplates (maybe 2017), but to me it seems LEGO didn't only change the packaging, but they slipped in a new mold using less material. Unless they already changed it before.
Here you can see the backside is already very different Pic1
These plates also seem to be made of e different less strong material, I hadn't even gotten home and one of them was already bent. Pic2
My biggest problem however is that there is a difference in height. The difference is very small, but enough that I can't connect a wall that is build over one of my old baseplates and connected to the new with the wall cracking over night. You can see the upper baseplate drops lower than the bottom baseplate.