With VisualStudio, while debugging, If I watch "System.Text.RegularExpressions.GroupCollection".Item[String], it gives an error.

I'm using Regular Expression in Unity (Unity2020.3 with Visual2019) .

As shown in the picutre below.

It is fine to use groups[str] in code to get the group.

But if I watch it when I am debugging , it gives an error.