Logged in user not recognised – treated as guests

Hello,
we need help with a multisite membership website.
We need NOT to cache logged in users, but on our producyion env. this configuration is not working.
It seems to be working on the staging environment, where we don’t have Cloudflare active.

The two logs says:

– Staging
[*****29:64580 2 1WP] [Router] get_role: subscriber

– Production:
[*****29:10058 2 K4y] [Router] get_role:
[*****29:10058 2 K4y] [Vary] role id: failed, guest

Production report number: XNWFXVKN
Staging report number: ZSLCVAUD

We need to fix this isssue urgently
Thanks