I'm also having this issue today. It's a real killer because I'm trying to schedule everything for next week while I'm on vacation. Hope they get it fixed soon or I'm going to have to schedule everything manually for each platform.
I have the same problem here. It's seriously disturbing. I hope I won't have to add line breaks to all the publications I've scheduled when the problem is solved... Hopefully this one will be fixed soon.
Thank you for posting this. I thought I was going crazy yesterday and this morning, busy googling and putting in a ticket for this. Please fix this, HubSpot.