After working with the Microsoft Support team for a few weeks, we realized that the Customer Workspace App has a limitation when switching to another tab. More information on it below, per Microsoft Learn.

"We have determined that we have run into a specific product limitation regarding Subgrid controls and have no workaround at this time. Please note that I am committed to monitoring updates closely and will reach out if I see a solution that will work in your scenario. "

We'd like to suggest a way to retain filters on a subgrid, after switching tab or sessions.