My Garmin can briefly record excessively steep grades if I zoom down a steep downhill, then immediately climb the other side. The sharp change in wind speed at the tiny barometer hole confuses it temporarily. It's otherwise okay.

Karoo 2 elevation error complaints
A quick google search shows lots of forum posts on various sites about Karoo 2 elevation errors.
google: "karoo 2 excessive elevation gain"

This post shows their elevation chart, with repeated short, sharp elevation spikes in the middle of normal road grades. More often on downhills, but also on flats and climbs. The summary says "max grade 55%" !!
There doesn't seem to be an accepted solution that works for everyone so far.