Why am I shooting way low with G42 & G43?

I would like your advice. Last July I purchased my first pistol, a G19. I received professional firearms training, dry fire almost everyday, and shoot my G19 pretty accurately at the range. I also have a PPS 9mm and Sig P238 and shoot both accurately. Last fall I tried the G42 and consistently shot VERY low at 7 yards. I had to aim high intentionally in order to hit the target. I tried the G43 last week and, as I feared, found myself shooting VERY low again, about 4" at 7 yards. I took my time, concentrated on my trigger pull. But I still shot low every time. As with the G42, I had to aim high intentionally to get the round where I wanted it to go. I know the G42 & G43 are fine pistols and most others shoot them with great accuracy. Why am I consistently shooting low with them? I can only imagine it's my grip. What do you all recommend? Thanks!

Why am I shooting way low with G42 & G43?