Problem whitelisting zscaler ips in GCP

Hi,

We are trying to whitelist a customer who is using zscaler.

We see that some of their devices show a source ip that comes from zscaler, and some do not.

In the cases in which they do not, the address appears to be their gateway.

We are using GCP on our end to host the whitelisting app.

Any idea why this might be happening?

Thanks

@Leigh_Stewart , could you please check if XFF is enabled on location configuration ?