the other 2 queries work for Database 19.3 as well...for what it's worth.
My sql/developer version is also 19.4
Java(TM) Platform 1.8.0_221 Oracle IDE 184.108.40.2064.1759 Versioning Support 220.127.116.114.1759
Right, i'm just saying it's good on database 19.3, and not for you on 19.5...you should really open a Service Request with My Oracle Support.
Maybe someone here with a 19.5 instance can try to reproduce what you're seeing as well.
Your use cases are easy to test, so it should be easy for MOS to start a ticket for you.
Thanks, i'll open an SR.
Apply patch 0557433. New DB-version:
"Oracle Database 19c EE High Perf Release 18.104.22.168.0 - Production