After Staging, Next Stage Prop Quantities Blank But dV is Expected Amount

[LameLefty]

Several times today I've encountered a situation where an ordinary 2-stage rocket doesn't seem to stage as expected. The after staging, from the ordinary flight view, the quantity gauges for both propellants shows empty, though the stage shows the expected 3,000+ m/s dV  available.  Trying to start the engine with the keyboard throttle controls does not work - the stage thinks its empty and the engine doesn't fire. The tank is a standard 2.5m methalox tank and the Resource Manager shows it completely full of both fuel and oxidizer despite the the display on the stage indicator. Most of the time, manually tweaking the engine throttle will trigger something and the stage prop quantities will display correctly after that. At least once tonight, however, that didn't work. I was able to go into the Parts Manager, select the engine for the stage, and after clicking the box to show the Advanced Controls, fiddling with the "independent throttles" control made the stage  propellant indicators seemingly wake up, and after that I could run the engines of the stage as exected.