BBC 198 kHz temporary power reduction in February 2023

Below is a plot of the signal strength of the BBC's 198 kHz signal as received in Enschede, the Netherlands in February/March 2023. Vertical axis is relative power in dB; carrier power has been averaged over 1-minute intervals and plotted as dots. Horizontal axis is UTC date.

We can see the signal level dropping some 2 to 3 dB weaker on February 23, and returning to its previous level on March 2. (Note that the received signal strength is quite variable due to propagation effects, but in the middle of the day the propagation is stable enough to see this.)
Perhaps the BBC did an (unannounced) test to see how much impact a power reduction (and associated energy cost savings) would have for the listeners?

(This power reduction was brought to my attention via the fr.rec.radio newsgroup.)