I ran into a similar glitch, so I'll report here. I ended up doing the get your cousins mission (triggered on the harvest quest) before doing the mission with the girl from the ice cream shop first (which allows you to go to the base the first time, with the purple haired girl showing you around)
After completing the mission and chasing off the guy that escapes (blow helicopter), you end up in the base (for the first time, but should really be the second), the girls go the the party near the pool but a copy of purple haired girl stays at the dock, if you talk to her, it'll trigger the interaction you have with her from the ice cream questline, where she'll show you around for the first time, you talk to the guy that betrayed you and ran but he's still there and all. If you enter the building following her, your character will simply freeze after some dialogue, no way out. Tried a few times and nothing worked. I ended up restarting the campaign and by luck I did ice cream first and realized what happened when i got to base first time.
I didnt realized at the time that i wasnt suposed to talk to her and go somewhere else, probably everything would be fine, but since she was part of both quests, i thought she was essential.
It was definetely a dumb person's (me) glitch, but maybe limiting the harvest quest that leads you to base only after you complete the ice cream questline or something could work, if you think that's necessary.
That said, the game is absolutely awesome, definetely a much more interesting and well made version of a game with similar artstyle, that is super famous and the creator continuously scams his 30k patreons with no content :wink wink:
You could definetely get a lot of followers if those fans get to know this game!
Congratz