In the past recovery time (immediate feedback after activity and from the performance widget) has always seemed consistent and to change in a reasonable way over time. But not in the last 24 hours!
Yesterday I did a tempo run. The aerobic training effect was 4.1 (still visible in history) and I think it said the recovery time was 34 hours. 9 hours later I happened to look at the performance widget (which has previously always been consistent with the feedback after a run) and it said the recovery time was 0 hours.
I think something in the code has been broken, unless you have some explanation I haven't thought of (or I have acquired a superpower!)