I’ve never heard of this exact symptom, but Toad doesn’t do well with BINARY XML. It’s been a long-standing problem.
You can work around it with GetClobVal, like this:
SELECT SY_UPDATES_XML.GetClobVal() as SY_UPDATES_XML,
FROM SY_HISTORY SY
You must include a table alias, or GetClobVal with throw an error. This workaround will be automatic in schema browser.
You’ll still have to code it manually in the editor though.
John