Recently we had to increase the field length (Maximum character count) of some Dataverse fields.
Everything was fine except for these fields which have been part of a Concatenate formula of another Power FX Formula Column.
There the update of the field size always brought up a SQL error so that we couldn’t save our customizations of the field.
Resolution was to remove the Concatenate formula from the other Power FX column that referenced these fields, publish it, than increase the field length of the affected fields and after publishing this again add the Concatenate formula again.
What I don’t know if it makes a difference: the Formula Column was indexed for search in Global Search in our case.