HTTP agent takes >10x longer to fetch an item than curl

[troffasky]

How to reconcile this:

2990855:20261028:111752.563 error reason for "OPNsense test:opns.raw.firmware.status" changed: Cannot perform request: Operation timed out after 4004 milliseconds with 0 bytes received
2990855:20261028:111752.563 error reason for "OPNsense test:opns.firmware.update.reboot" changed: Cannot perform request: Operation timed out after 4004 milliseconds with 0 bytes received
2990855:20261028:111752.563 error reason for "OPNsense test:opns.firmware.update.status" changed: Cannot perform request: Operation timed out after 4004 milliseconds with 0 bytes received
2990855:20261028:111752.563 error reason for "OPNsense test:opns.firmware.update.status_msg" changed: Cannot perform request: Operation timed out after 4004 milliseconds with 0 bytes received
2990855:20261028:111752.570 error reason for "OPNsense test:opns.firmware.update.count" changed: Cannot perform request: Operation timed out after 4004 milliseconds with 0 bytes received

which is this item:

https://github.com/zabbix/community-templates/blob/6fe9e500dcf594be400cc040b2ed9b422d63f511/Network_Devices/OPNsense/template_opnsense_by_rest_api/7.0/template_opnsense_by_rest_api.yaml#L673

with this performance with curl, from the same server:

# time curl -k -u "$key":"$secret" https://firewall-ip:20443/api/core/firmware/status &> /dev/null

real 0m0.218s
user 0m0.016s
sys 0m0.000s

There is no DNS involved here, going to straight to IPv4. This consistently times out on two different OPNsense hosts, and always returns in <0.5s with curl. This is *at least* 10x longer, and usually 20x.

I've made it work by overriding the master item timeout to 10s, but I am baffled by the difference in performance.