VTOL exceeding groundspeed limit

The other day I was bringing a VTOL plane ( with 3.9.9 stable) back to its take-off location from some distance away in QLoiter, when I noticed visually that it seemed to be traveling very fast, much faster than the Q_Loit_Speed set at 300 cm/s. The log shows that it got going a little over 10m/s before I saw it and slowed down (it was coming right at me, so speed was difficult to determine speed visually). See below for log excerpt.

I was able to replicate in SITL on 3.9.9, but the problem didn’t happen in 3.8.5 (SITL or IRL) with same setting/hardware.

We recently moved to 3.9.9 from 3.8.5 and this is the first major anomaly we’re noticing @tridge . (another include the loss of function of the RX_RSSI)