PowerShell v6.2.0 preview 4 is now available from https://github.com/PowerShell/PowerShell/releases
After installation over the top of preview 3 I found that the PowerShell console would open and then immediately close when I tried to use it. This is a known issue with a fix in the pipeline as far as I’m aware. The workaround is to re-run the installer and select the repair option.
The conflict between the Working directory and profile seems to have been resolved with the profile taking precedence.