OK, so I base this tip on fact that the first clearly fixed match of this tournament was seen yesterday by China who needed to give 2 penalties because Uzbekistan didn't seem to be able to finish otherwise. First penalty came from a "textbook of match fixing" tackle from behind even if the ball was heading out from the danger. 2nd penalty came from a very intentional looking handball. With VAR in place, if you extend your arm towards the ball and practically make a hitting move inside your own penalty area, there can't be any other outcome. It was Shanghai Shenhua's Zhu Chenjie who committed the foul, so it shouldn't have come as a surprise because despite his young age, he has fixed many matches before.
Now that the match fixing has been officially and undisputedly opened for this championship there is no reason for North Korea, China's sidekicks in match fixing, to hold back.
In 2016 AFC U19 North Korea were in almost same group (Vietnam, Iraq, UAE). They tried their best in first match against Vietnam but lost that match 1-2 (like they lost against Jordan last week). After this they fixed both remaining matches (universally agreed, nothing unclear about this). Almost half of the starting lineup from AFC U19 2016 survived to AFC U23 2020, especially the defenders.