In message <QgWztYCDa8HhFwG$@brattleho.plus.com>, at 16:13:07 on Fri, 20 Aug 2021, Ian Jackson snipped-for-privacy@g3ohx.co.uk> remarked:
Any kind of repair mid-shift will delay flights for the rest of the day.
He's the guy who sells rubber hamburgers
Which flight is this: the one I was on, or the one the OP observed?
People probably only notice the flights which get turned back, not the ones which limp on. So anecdata to determine a ratio is probably futile.