Found a glitch on the PC version:
I assume I'm supposed to be able to talk to mabel and our flying foul friend on their date, but no notification to talk pops up. During the two's meeting, I called for penny for a chat and canceled, showing the notification for a chat, and a golden question mark to appear. is it possible it's not allowing the conversation due to still being able to call penny?
Update:
I went to chapter select in hopes of fixing it. while it was fixed, I also got to notice that the sweater/jacket (whatever) appeared in my inventory after the fact, so possibly another problem? while the game acknowledged that I did have the sweater (I could go up the mountain) it never showed up in inventory unless I used chapter select