Selecting a diferent mesh doesn't reset the Z height

[JaVelin-X]

This is probably a simple one but it's worked for me before. On my B1 I had to change the marlin version when I put an SKR 2.0 board in, but uses all the same settings as it did before with just the insane UBL from Luke. I had intended to use the different saved mesh slots for changing build surfaces but never used it much, maybe just once or twice when this printer had the old board. I tied it last night and it worked, made my print on glass in place of the spring steel sheet, but when I went back to the mesh i normally I use with the steel it tried to print at the higher Z height as if the glass was still there. To get it back to normal I probed a new mesh and it works ok now but I don't see how it went wrong.