Session data lost after redirect randomly (CI4.1.5)

If you use Ajax heavily, do you set the request header X-Requested-With?
https://codeigniter4.github.io/CodeIgnit.../ajax.html

I'm not 100% sure, there is old angular v1 implementation for those. Anyway, thank you for the suggestion, I will try to add this header and will write here in some time to let you know it it helped.