Is this a stable approach?
No that does not appear to be a stable approach for all the reasons already mentioned.
Perhaps there is some reason for this display of "airmanship". I do not have all the information, but as it first appears it does not reflect well on this crew.
Sometimes "good people" and otherwise good pilots make poor decisions. One example might be the (USA) RJ accident when the crew, without anybody else on board, put the jet "through its paces" and flamed out both engines. They were killed when they impacted the earth short of an airfield they were trying to make when they were unable to restore thrust. From that accident came an industry information campaign on the "core lock" event of a turbojet engine under certain unfavorable conditions.
Was there some malfunction they were compensating for (as the poster above indicates). Was it sanctioned training, or some sort of flight test? Perhaps they did a stellar job then, and my concerns unfounded. Without more information the approach looks unstable to me.