I'd not take anything that's reliant on speculation and deductive reasoning to imply insider knowledge.
"What was discovered during her stay" is intentionally vague, as it can mean anything from a discovery during surgery to a failure to heal properly to an unrelated clinical issue. It could also be as simple as she went in for an exploratory procedure to confirm a diagnosis and confirmation led to immediate treatment.
If the royals do choose to elaborate on her condition, that vagueness can now be claimed to have been proof of insider knowledge for any number of outcomes, and as a result ensure people think of the next vague and empty speculation as from a trustworthy source.
"What was discovered during her stay" is intentionally vague, as it can mean anything from a discovery during surgery to a failure to heal properly to an unrelated clinical issue. It could also be as simple as she went in for an exploratory procedure to confirm a diagnosis and confirmation led to immediate treatment.
If the royals do choose to elaborate on her condition, that vagueness can now be claimed to have been proof of insider knowledge for any number of outcomes, and as a result ensure people think of the next vague and empty speculation as from a trustworthy source.