Interesting but sounds like CAT
Interesting possibilities and it remains to be seen after the DFDR has been decoded. However, in this part of the world at this time of year, in addition to the jetstream, there is a change in monsoons from from SE to W, which can also cause problems. Recall a similar incident sevral weeks ago involving a China Airlines 744 approaching DPS (Albeit further NE) which appears to have involved a substantial reduction in FL as a result of what seems to have been only CAT.
I have had a similar experience in a CX L1011 over the S China sea which hit CAT and dropped 3-4,000 M in a few seconds, involving several weightless passengers hitting the roof with several injuries and missing teeth etc.
"We recommend that when seated pasengers keep their seatbelts loosely fastened, just like we do up here on the flight deck"
Can this please be used as a simple illustration to ordinary travelling folks as to why this is the case?
Of course, there is no protection against being hit on the head by the corner of a flying meals trolley but, unfortunately, I don't see that changing anytime soon.