Error running Backwards Compat

Latest commit:d6b28a40 Running backwards Compat on my current save greets me with this message

https://puu.sh/FihhW.png

Legit.save

Ty.

Known issue, closed by !6283 (merged)

mentioned in merge request !6283 (merged)

closed via merge request !6283 (merged)

mentioned in commit ece887dc