The problem with calling serves is that it isn't consistent at all. In the FZD vs. LJK match, they kept calling LJK for not tossing the ball vertically enough. FZD's serves were just as off vertical as the ones called on LJK but were not called.
It makes you whether there is an ITTF agenda to pick on a particular player in order to favor someone else. I'm not saying there is some deep conspiracy going on, but if you are going to call serves, call them consistently on ALL players starting with game 1 of match 1 in the qualifiers all the way thru the finals.
Either all players will adjust very quickly or all points will be lost on called serves. And that will be the state of table tennis - no rallies, just points won or lost on called serves until a sea change happens. The current inconsistent enforcement of serving rules is ridiculous. Calls are made at crucial times in a match that impact a player's flow due to their random calling.
Or, maybe just maybe ITTF needs to rethink its serving rules that are hard to judge and enforce consistently from the umpire's seating position.