It’s not a bug – it’s an undocumented feature.
Hi Zwiftpower,

My profile skills:

is not showing update from 1min power from event on Sept 11:

Looks like it would show up as one of top three 1min Watts and 1min W/kg efforts in race events thus far.

I noticed a similar issue in my case

My profile has not been updated to include the 1m wkg effort from yesterday's 1 lap WBR event. I noticed that both in my as well as in Bryan's case, the 1m wkg effort was attained during a short 1 lap race (no green lighting bold at the beginning of the line). I understand this occurs when a race was shorter than 20 min (or it was a ride with a late join). I reckon this might have something to do with it?