Pipedrive recording Google Ads GCLID as [gclid] instead of actual value

We are using Pipedrive to report offline conversions - when a lead converts further down the sales cycle we send a conversion to Google Ads with the GCLID.

We are seeing some records come through where the gclid parameter’s value is [gclid] instead of the actual gclid value.

What would cause Pipedrive to record the gclid parameter as [gclid] rather than the user’s actual gclid value?