How new is this pistol?
For a moment, I'll assume that it's brand new. If that's the case, look closely at the trigger safety, the part that protrudes from the front of the trigger and is pushed back to allow you to move the trigger back. On some new Glocks, I have seen what a factory Glock Armorer called "flash molding", which is the presence of excess plastic molding on the sides of the trigger safety. That was present in one pistol that was exhibiting a strange "jerky" trigger pull that I saw, and the solution was to very carefully file it flat. This "flash" will appear as two ovals (not perfectly oval, more like Indianapolis Motor Speedway oval), one on each side of the trigger safety. If it's there, and if you can feel it catching the trigger, you can file it flat (with very fine files), and clean it up with fine sandpaper.
Another thing I would check is the fit of the connector in the trigger mechanism housing. I've seen sticking here on a couple of different (non-Glock) connectors. In order to see it clearly, you need to detail strip the bottom half of the pistol, and disconnect the trigger spring so that you can remove and examine the connector and the trigger mechanism housing closely. The connector should stick out from the trigger housing at the top (or rear), it's designed to spring in and out. If you push it in and out and it doesn't catch, it's fine. If it does catch, my solution has been to remove the connector and carefully file the edge of the trigger mechanism housing where the connector is touching it. Once that's done and the connector move freely, the trigger feel should improve.