Spindle speed not set.

I have a spindle that is connected to a PWM output. I want to use the buttons on the Manual Control screen to run the spindle.  To do this, I go to the MDI screen and issue an S command to set the spindle speed.  If I use M3, M4, and M5 from the MDI screen, it works properly.  If I switch back to the Manual Control screen and use the forward button, the spindle speed gets reset to 1 and the spindle does not turn.  I verified the spindle speed being set by looking at the HAL data.  I have reproduced the behavior on a couple of different builds of 2.8.  I know in the past (a year ago) it did work properly.

I added the DEFAULT_SPINDLE_SPEED and now when I use the buttons on Manual Control screen I get that speed.

Thanks for the help.