PS 7 and PS 5.1 that ship with PSU are not the same as the integrated environment. While they are integrated into the install media, they run in a separate process (PowerShellUniversal.Host.exe) and do not load all their assemblies into the main PSU server.
The Integrated environment loads all assemblies into the main PSU server and can cause some cross contamination between assembly versions and static values, especially for modules like PowerCLI, Graph and Exchange Online.