Pumpkin stems connect to the same pumpkin when one grows

I made a pumpkin farm to grind emeralds from farmer villagers and noticed that when a pumpkin grew next to two stems they both connected to it, preventing the one that didn't grow the pumpkin from growing a different one. This is annoying because I get less pumpkins that way.

How to reproduce: Plant two pumpkins next to each other and wait for a pumpkin to grow next to both stems. They will both connect to the pumpkin.