At work, I have a library of modules stored on a network share. In order to make things work well when I’m not on the network, I include the network share in my PSModulePath, but later in the PSModulePath I point to a local copy of the library.
Since installing the 5.0 preview (which I love, btw), I’ve seen some really strange errors, like this one:

Obviously, I am not redefining the set-variable cmdlet in my scripts. I’ve had similar kinds of errors with clear-host and other “core” cmdlets. FWIW, the cmdlets that error while loading the profile seem to work fine after everything is done loading. Clearing nonexistent paths out of the PSModulePath makes the errors go away.
If you have to include network shares in your PSModulePath, I would recommend adding them in your profile, and use test-path to make sure that they are available before making the modification. T

I’ll chalk this one up to it being pre-release software. It’s encouraging to see the PowerShell team continue to deliver new and exciting features with the speed that they have.

-Mike