Spotty API updates with homeassistant.update_entity

Just getting to grips with REST sensors and API’s; managed to get my Ambee sensors all worked out about two days before the official integration appeared .

Curious about one bit of behavior:

I have a view set up on Lovelace which fetches dog pictures (TheDogAPI) based on a selection in a nearby dropdown. The image and some related facts are rendered in a markdown card, and I have a button set up just under that to force a new API call (thus loading a new picture and set of doggo facts).

It works well enough, but the behavior is inconsistent. Sometimes refreshes happen smoothly, other times the markdown card remains blank despite my insistent attempts at refreshing. I’m convinced its a HA problem rather than an API problem, since my GET calls to it from a different client (Insomnia) always come back quite promptly.

Any insights from those with more experience?