How to display throttle % in OSD during RTL?

I noticed that although I have OSD1_THROTTLE_EN = 1 to display the “actual throttle percentage being sent to motors”, when I switch to RTL, it usually shows 0% even while the motor is running at a fine speed for bringing it home and circling. THR% displays correctly for Manual and FBWA modes.
How can I get it to show me what % Thr the RTL (or other automatic modes?) is using at any moment?

I am using Arduplane 4.4.1 on a Matek F405-VTOL FC.