if an active lease (even one matching the current host data) is attempted to be provisioned, the core will raise some like this:

ProxyAPI::ProxyException
ERF12-4395 [ProxyAPI::ProxyException]: Unable to retrieve DHCP entry for 52:54:00:33:b5:df ([Net::LeaseConflict]: 52:54:00:33:b5:df/192.168.123.52) for proxy https://foreman.hostonly.sapphire.elysium.emeraldreverie.org:8443/dhcp
lib/proxy_api/dhcp.rb:53:in `rescue in record'
lib/proxy_api/dhcp.rb:43:in `record'
lib/net/dhcp/record.rb:41:in `conflicts'
lib/net.rb:27:in `conflicting?'
app/models/concerns/orchestration/dhcp.rb:140:in `dhcp_conflict_detected?'
app/models/concerns/orchestration.rb:47:in `valid?'
app/models/concerns/foreman/sti.rb:29:in `save_with_type'
app/models/taxonomy.rb:41:in `block in no_taxonomy_scope'
app/models/taxonomy.rb:48:in `block (2 levels) in as_taxonomy'
app/models/concerns/foreman/thread_session.rb:143:in `as_location'
app/models/taxonomy.rb:47:in `block in as_taxonomy'
app/models/concerns/foreman/thread_session.rb:108:in `as_org'
app/models/taxonomy.rb:46:in `as_taxonomy'
app/models/taxonomy.rb:40:in `no_taxonomy_scope'
app/models/concerns/foreman/thread_session.rb:33:in `clear_thread'
lib/middleware/catch_json_parse_errors.rb:9:in `call'

This is due to 90ff2a3a4eaa07af0f9521468a978701cf21981f which added extra validations to the dhcp orchestration.