I can not program Flows in version 12.7.0. existing flows can not be edited.
What type of Homey and what type of user account?
What have you tried already to solve the issue?
1st, When you encounter issues after an update: first cut the power from Homey for 10 minutes
If that doesn’t change anything:
2nd, Is it solved when you open the my.homey.app web editor in a private tab?
(this forces all data to be fetched from zero)