Why does the site always remain cached on some mobile devices?

Question

Nginx

Good afternoon!

On some mobile devices, the site displays an error in which it apparently once cached (here I'm not sure, but this is such an educated guess). There is an observation that the site gives an error on any new device, i.e. where it has never been opened. At the same time, on devices that display the site normally, there is a delay in loading, the loader slider and all other evidence pointing to a workable site are visible. On devices that give an error, this happens instantly, i.e. there is no loading time.

The logs are all empty, since there is apparently no error on the server side. TTL set the minimum value - 10 minutes.

We are talking about the site https://kosher.ru

The original of my request on SO is here -https://stackoverflow.com/questions/67781422/rails... although I seem to have adopted everything (thesis) from there.