Probably because there are more and more companies that need access to this API (home batteries are very popular at the moment, and more people check dynamic prices often than before). So the API (third party) that Homey uses might have no more capacity
I agree on this, but Power By The Hour is a great alternative, that despide also have an occasional issue with no data, is more reliable. In my experience the no data issue is resolved faster.
Exactly this is the reason I’ve built my EV charger flows bases on the PbtH cards for energy pricing.
If Homey wants to become a HEMS, this should not be happening so often and they should provide a RCA of the issue. A lot of integrations are based on good and accurate energy prices.