To reproduce:
1) Open Unity
2) Click "New Project"
3) Click "..." to browse
4) Select a different directory - it doesn't get updated

Only happens first time on launch, and I have barely managed to reproduce it a couple of times. When trying to replicate conditions like the ones when I caused the bug, it suddenly doesn't reproduce in that way but after several more attempts ir reoccurs again
I guess one "reliable" way(managed to hit it three times in a row and then fail reproing it again) would be to create a project in D:\whatever so the default would set to there, then when creating a new project and browsing for a directory, browse through many different folders (at least 5) and then select something in C:\ after all that browsing.