When Browser Content Redirection is active, pressing the Print Screen button or using Win+Shift+S to capture a screenshot will only capture the frame of the Internet Explorer or Chrome window.

This is a limitation of the feature, as the screenshot will be captured within the session, but the BCR windows is drawn only on the client device, capturing screenshots within the remote session will not show the window content.

Instructions

To work around this limitation, a screenshot needs to be captured from the client device, as BCR windows are only being drawn on the client device, and overlays the remote session, capturing screenshots within the remote session will not show the window content.

Workaround (Capture screenshot from client device):

Select the Desktop Viewer toolbar.
While the cursor is focused on the Desktop Viewer toolbar, press Win+Shift+S.
Use the cursor to draw a box to include the the desired image.
Now the paste buffer is loaded with the box content.

Alternatively, while the cursor is focused on the Desktop Viewer toolbar, press Print Screen button.
Now the paste buffer is loaded with the contents of the entire endpoint desktop, including the remote desktop with the redirected browser contents.  If there are two monitors, the Print Screen button will capture both.