Update msbuild-props.md

Author: JanKrivanek

docs/core/project-sdk/msbuild-props.md

@@ -1783,7 +1783,7 @@ In addition to the standard [MSBuild item attributes](/visualstudio/msbuild/item
 
 ### CopyToPublishDirectory
 
-The `CopyToPublishDirectory` metadata on an MSBuild item controls when the item is copied to the publish directory. Allowable values are `PreserveNewest`, which only copies the item if it has changed, `Always`, which always copies the item, and `Never`, which never copies the item. From a performance standpoint, `PreserveNewest` is preferable because it enables an incremental build.
+The `CopyToPublishDirectory` metadata on an MSBuild item controls when the item is copied to the publish directory. Allowable values are `PreserveNewest`, which only copies the item if it has changed in the source location, `IfDifferent`, which only copies the item if it has changed either in the source or target location (helpful for situations where we need to reset changs occuring after the publishing), `Always`, which always copies the item, and `Never`, which never copies the item. From a performance standpoint, `PreserveNewest` is preferable because it enables an incremental build. `Always` should be avoided - as any scenarios requiring it should be achievable with more effective `IfDifferent`.
 
 ```xml
 <ItemGroup>