From the sounds of this post, a Matrice 300 augered in after receiving a couple of errors.
The issue with many quadcopters is they are not designed to fly on three motors. We also don’t know the reliability of the motors being used. I’ve never seen any Mean Time Between Failure (MTBF) data from manufacturers.
In public safety, we need to remember to fly these drones as if they are always going to come down. As this FDNY pilot said, “As sUAS Pilots, we should be operating our craft as if it can fall out of the sky at any given moment without warning.”
The aircraft propulsion error could either be a motor failure of a component in the propulsion system. In the past, with the Matrice 210, we saw many Electronic Speed Controller (ESC) failures.
The satellite signal error is a bit more perplexing without additional information. However, the installation of aftermarket equipment on drones that can interfere with GPS is a worry. This is especially true of anything installed above the aircraft.
In my opinion, the fact the pilot received these two warnings would logically indicate a more severe hardware or software failure since the two systems might not have a logical connection.
With the weight of the M300, we are very lucky that it did not come down on someone, the impact could have been fatal.
Always fly like it is coming out of the sky.