Game crashes the same day I give a mermaid pendant to Shane

Hello, whenever I give a mermaid pendant to Shane to propose, this pops up in my SMAPI: https://i.gyazo.com/c54677be072e3c4f5d0536d14c431110.png

When I go to bed that same night, the game crashes immediately. The window closes.

I have tried removing all mods to see if the problem keeps happening, and it does. I ran this one with zero mods, and Shane won't accept my proposal. He just says I'm crazy for trying to propose to him when I already proposed to someone else, when I never proposed to anyone but him.

I am playing multiplayer with SMAPI 2.6-beta.16

Can anyone help me figure this out?