Party Invite Bug

I can send a party invite but it does not appear to go through on the other side.
I get a request for trade. I invite the other person. Nothing happens.
If I click on their name again, I have the option to kick from party... but they are not in my party. Kicking them lets me re-invite with the same results.
If I do nothing, I will get a message ~1-2 minutes later saying that the party was disbanded.
In the meantime, the other player will be repeatedly messaging me for a party invite.

It seems like I can accept party invites, just not send them. Please help!