datapatch doesn't apply patches to the database.
We have a number of new 19c database installations on Windows 2012R2 that have had the 19.9 bundle patch and ojvm patch applied on the binaries. Running datapatch it fails to apply the applied patches to the database, it doesn't error it just says that there is nothing to do but it doesn't report that the patches are applied.
We have another installation on Windows 2016 where this process works fine and datapatch reports that the patches have been applied successfully.
AFAICT the problem is with the OPATCH_XML_INV table which actually runs a batch file on the OS to get the patch status of the software. This is returning no data at all on the non-working systems but is on the working ones. Running a select on from SQLPLUS if just returns instantly, like it is running the batch file at all whereas on the working system it takes a few seconds and returns the XML. If you look at the rdbms/log directory you can see the log files from the process and previous runs on the working