Hey there!
Were there any changes to Zaraz around May 24th that would have affected how parameters are set for the first_visit/session_start events?
Ever since ~May 24, we've been receiving parameter values set as "{{ client.xyz }}" in our first_visit/session_start events. We have all our GA4 data exported to a redshift table daily so we are able to query it and determine that this is occurring only for these 2 events, and the parameters are set for all our other events...