bh.wrng.user.sh.time error while creating a meeting within a blueprint checklist

bh.wrng.user.sh.time error while creating a meeting within a blueprint checklist

I have a blueprint transition in which i am attempting to "book" a meeting for when the user selects the "book installation" transistion.

as part of the checklist i am requiring the user to create a meeting with one of the fields being to set the "host" 

if the host is part of the blueprint "During" transistion, it throws an error as soon as you make a change to the To or From or Host fields

bh.wrng.user.sh.time

its causes a popup on save that reads

bh.wrng.user.sh.time error do you wish to save anyway?

Its seems to save fine but i dont want errors like this popping up confusing staff members.

if the host isnt added as part of that blueprint checklist the error doesnt occur