I unsuppressed one flange, which brought back flanges on many edges BUT I don't know which flanges are supposed to be suppressed. There are a number of flange features in error, some of the errors could relate to suppression of other features (so edges no longer available).
All I can really advise is don't let errors accumulate in a design. Resolve errors as soon as they are triggered - probably by whatever you just did (so at least you'll have some clue). If there are many errors it becomes very difficult to diagnose the problems.
If you are trying different alternatives in the same file, use configurations to manage feature suppression.