Cant create folder with name "Z1" in this current folder

2) How can we reproduce it using the example you attached
1 Open attached project
2 Go to Assets folder in the Project view
3 Remove folder "z1"
4 Try to create folder "Z1" - the folder name will be "z1" but should be "Z1"
after reporting a bug appeared warning:
"Renamed .meta file 'Assets/z1.meta' to 'Z1.meta' because the .meta file had an inconsistent case."
After this warning the casing of the folder name fixed itself and the folder was called Z1.

Bug appears only in Assets folder and only with "z1" folder