I'm getting this as well! I can't put any wolves in my party at all after I tried clearing it to see if it would fix itself. I guess I won't be able to find any wild wolves for a while :/.
I'm having this error every time I try to switch a party member out of my campaign party. I have to remove them, save the party, explore at least once before it works and lets me add new campaign party members. Refreshing the page doesn't fix it for me.
Also coming in to say that I regularly experience this bug, usually when switching out party members. I just have to refresh the page and try again to get it to work.