When inserting features into a table in an Oracle Datastore, if the table name contains underscores, then:
The primary key lookup will fail:
Because the primary key lookup fails, the primary key is null and we get a read-only FeatureSource, causing the insert to fail:
This is particularily notable when using the importer extension to import shapefiles.
It looks like this error is related to the changes made here: https://github.com/geotools/geotools/commit/3a98d302b9f41006e33da51cc107ba7449e471f9 (Fix for GEOT-4912 Open )
GEOT-4968 Open seems to be caused by a similar problem.