Really surprising considering that Oracle is the standard for serious enterprise databases.
Not really surprising when you consider Oracle's other bug ridden offerings (probably not as thoroughly tested).
Makes me fear for Oracle 18c.
The field of software engineering has matured a lot since then.
There are quite a few very old projects that don't have the same level of cruft as Oracle; it epitomises a Sales Division driven culture.
How many of those switches (that now need to be supported and tested) are because some functionality was promised to a large contract, and so it just had to be done? I would wager a good number.