Yep, that is why in Post #34 I asked if Smart IR was on - at that low height, that IR bounce will wreak havoc on the IR as you saw with the pulsating as the camera was trying to Smart IR to eliminate washout and will throttle back the amount of IR.
You will see a big improvement tonight in the amount of IR. You will probably have to manually tone it down due to the height, but you will get better control that way.
Smart IR works in certain situations, for many, manual is the way to go.