Issue Description

We think we found a regression in MSBuild on VS 17.5.0 Preview 2.0. Apparently a property is disappearing when an item is being added to a collection.

We call a task with some items. They go in and come out correctly (they have the BasePath property).
We add the outputs back to the item group.
When they are added, the BasePath property is missing.

Steps to Reproduce

• File new project MVC with (individual auth)

Expected Behavior

Metadata items are preserved

Actual Behavior

The BasePath metadata item is lost

Analysis

Analysis is above.

Versions & Configurations

MSBuild version 17.5.0-preview-22558-04+15b127d24 for .NET Framework
17.5.0.55804