I have a real problem with pieces like this that define "recession" in terms of abstract measurements of bits of the economy. Real recessions are about actual people and their lives, and although there's a definite correlation between the sorts of measures cited here and people's lives, it's much weaker than the article implies. We have very low unemployment right now, and most the features of a people-affecting recession are absent. Yes, the economic situation is really complicated and has some worrying signs, but calling it a recession based on the quoted numbers even when they are embedded in a not-seen-in-100-years context seems rash to me.
"The NBER defines a recession as a significant decline in economic activity spread across the economy, lasting more than a few months, normally visible in real GDP, real income, employment, industrial production, and wholesale-retail sales."
Like another comment said, recessions hit the ordinary folks last. But their stress is already evident. Employment numbers can turn on a dime. as can retail sales.
RPI is down because of inflation though, not because of a decline in GDP, increase in unemployment etc. So yes, uncharted territory but not necessarily on the recession continent.
This is circular reasoning. It's also wrong as a general claim. Personal income, at least as traditionally measured, fell for a large number of US workers over a 35+ year period during which inflation was non-zero and yet there was not a recession covering the entire period.