if you change the case of a folder the content browser retains the original case
if you delete the folder and delete the system folder and recreate a new folder same name different case the folder in the content browser path line retains the previous folder case
This is a known bug. And the devs has acknowledged it. I heard this is because of the way FNames work (they are case insensittive). So abc, Abc, aBc are all the same.
Here is the explanation:
We’ve made a change for 4.5 which will make FName case-preserving for the editor and UHT. This should address the FName case issues you’ve been seeing.
I’ve checked that you’re able to rename asset, actor, and blueprint components in a way that changes only their case. I’ve also tested that you’re able to have a variables in different UObject/UStruct types that vary only by case, and that the UHT will generate code that actually compiles.