since about two days I sometimes get the same error, too - except that unlike the other people who reported it, mine doesn’t load the actual results after a few seconds. However, I’m one of those very rare Firefox users which might explain the difference in behaviour
According to the dev tools, the culprit seems to be this XHR call:
https://api.bunpro.jp/api/frontend/summary/last_session?review_session_id=[reviewid]
which takes a lot of time and the empty page renders before the response arrives.
In the case of this small review (5 questions) the response took 600 ms to arrive and did render the page. My previous review was ca. 50 questions, and there it didn’t render. I assume it took substantially longer with the more questions, and some other event fired in between which led to it no longer rendering based on the response.






)



I guess I will have to check each time if it is actually preserved on the main screen, but just wanted to let you know!

