On many of the 90's imports from China,,mismatched parts prevailed.
Check the TD latch and make sure it's engaging the cut in the frame as it's supposed to and that the V spring leg from the lock assembly that powers it is in fact giving it full force in engagement.

Quite a few that I've had to work on had the mismatched part. They were OK if fitted with some skill.
Many were crudely filed so they would just drop into position when the upper and lower were assembled, no sense of any fitting. Just file a bunch off of the semi round surface of the TD latch engagement so it dropped into position.
Some were so sloppy you could back off the upper from the lower unit enough while it was assembled that the pistol would not fire.

Some had hardly any spring tension on that TD latch to hold it down in position when the pistol was fired.

The cocked hammer holds it down when the pistol is in that mode.
But as soon as the hammer starts to fall, it's up to that small V spring to make sure the latch remains seated.