Some really insignificant bugs I noticed regarding the "Girls in Love" stat/feature.
Tested on Waifu Dreams City Build 79. But I didn't see it mentioned in the patchnotes for build 80 and 81.
1. The 2 interactable machines in the room next to the dance club have the hearth icon, but can't be filled.
I suspect they also count to the "Girls in Love" stat, as the highest I found is 149 / 151.
Edit: As torolatorre mentioned, the doctor where you respawn also has a heart icon that can't be filled.
Neither count to the "girls in love" stat.
2. On floor 4, immediately on the right, the dildo machine is sentient and can "fall in love". Iirc it did count to the "Girls in Love" stat.
3. The NPCs that you can bring to your home by default will have their love reset to 0 when you restart the game.
This happens for the slime maid from floor -1, Leila the giant from floor -2 and Ari the mermaid from floor 13.