Definitely looks like a cpr stall - in reverse thrust.
Essentially it's the result of loss of pumping capacity by one or more stages in the compressor, resulting in the remaining stages being overloaded and losing their ability to contain the high-pressure air in the combustor section. The fuel-air mix "burbs" out the front, then reingests and blows out the back. Generally sounds like a cannon shot!
It may be a very transient phenomenon, a temporary mismatch between stages. During engine accel it's likely to be the front stages trying to pump more than the aft stages can deliver to the burner. Engine developers work hard to prevent this, but r/t and especially crosswinds can defeat their efforts.