Firewall rule - 'is_timed_hmac_valid_v0' not entitled

Hi,

I’m trying to use the function is_timed_hmac_valid_v0 but I got an error.
Screenshot 2020-10-15 at 16.53.48

As doc explains, only other than Free plan can use this. I verified and we are Pro plan at my company.

Do you guys can reproduce this issue?
Is this a bug ?
Do I need to do anything else to make it work ?

Thanks in advance