Problem with shared tabs

So im having a problem with Shared tabs. I went on holiday with my girlfreind and we all have a bit list of payments we made. to settle up we made a shared tab as we had before. She clicked all of the payments she had made and added them to that tab in one go but when I tried to add my payments to tab I get the message “You cant split multiple bills unevenly”. I have to now add individual payments into that tab and cant bulk add anything. Same for all my shared tabs. Ive tried deleting it and starting again but having the same issue. Its odd as hers is working fine :confused: