When you originally bring the feature into your ArcMap session it's probably "owned" by another user. The other user created the data and therefore owns it. When you open your geodatabase and copy the data into your feature class you know "own" it within your spatial database connection properties.
Go to the original feature class, in a connection with the data owner's connection properties, right click on it and choose Privileges. Enter your credentials and grant View and Edit permissions.
Let me know if that helps.
I am having this exact issue right now with a 10.7 EGDB on SQLServer. The error affects all the feature classes in certain feature datasets but not all of them. Users with full privileges can view data but are given an error that there is no editable data. A quick fix I have just tried is to make the database users members of db_datareader and db_datawriter but if there is a better fix I would like to implement it.
Can the data owner successfully start an edit session without being added to the fixed database roles?
Are there any feature classes in one of the problematic feature datasets participating in relationship classes and the editor doesn't have permissions on the related tables?
Please create a support case and let us review the behavior if the above troubleshooting questions do not help. We might start testing with a new user with only edit permissions on one of the problematic feature datasets (the db_datareader and db_datawriter roles will not be applied). An sdeintercept can be set up to log actions for the 'start editing' operation and it will be reviewed for any errors.
Thanks
I always forget about sdeintercept. When I connect as the sde user, all the feature classes are owned by sde, I can edit anything. I removed db_datareader and db_datawriter from my domain user in the database and tried to connect with an sdeintercept set up. When I add a feature class from a dataset I can edit the contents of the dataset is recorded in the output as "User Privileges: SELECT, UPDATE, INSERT, DELETE" but when I add something from a dataset I am blocked from editing only "User Privileges: SELECT" is recorded for the data. I checked and do have full privileges for both datasets. I will open a support ticket in the morning on this.