A lot of folks seem to take it as a fact that the aircraft was temporarily recovered, briefly climbing, just before crashing - according to the tracking site. Watching the videos, if they are accurate, this seems highly unlikely though.
Remember, the altitude data from ADS-B / FR24 site is a barometric pressure reading transmitted by the aircraft itself only. Sure, in normal flight, a reduction in barometric pressure correlates with a gain in altitude. But when an aircraft left controlled flight, there are other reasons which could cause a temporary reduction in barometric pressure at the static port - which would falsely be interpreted as a brief climb.
So, what you should take as a fact is: we don't know...