Production plasmic page is using a staging env vars

there are sometimes where a production plasmic page is showing staging page content (is using staging environment variables).
we are using nextjs with runtime environment variables (next.config.js: Runtime Configuration | Next.js).
any idea what can cause it?
I noticed it happens to me after a while of not entering the site. refresh solves the problem.
Probably some Plasmic cache problem?
BTW we have this problem with some custom code component we registered, that uses these env vars.

Tabnine Team.