Treshold Power calculation

I have done 20 minutes test outdoor and calculated my TP to be around 187W. Strava caluclated the same value automatically. For couple of days I train indoors and also started to use Xert. On Strava I see significant drop of my TP to 154W (probably because I switched to indoor cycling) but this drop is not visible in Xert (yet?). In My Fitness section I can still see 187W as my TP. Is it going to change automatically at some point? Shall I avoid any manual adjustments?

It will automatically decline when your activity has maximal efforts (at least 5 seconds). The sensitivity to detecting a decline increases over time.

If your TP dropped off very quickly, we may not pick it up immediately in which case manual intervention may be needed.

Ok. Thank you.