ITEMS API - POST to /items/{id} Fails Outside Postman — Always Returns 405

[Invely]

Hello Team,
We've been integrating Loyverse via API and ran into a puzzling issue. We'd appreciate your help in understanding or resolving it.
What Works:
•    Creating new items via POST /v1.0/items
•    Updating items via POST /v1.0/items/{id} only via Postman
•    Authorization: valid Bearer token
•    Payload: full item + variant object, conforms exactly to your API schema
What Fails:
When making the exact same update request from:
•    Supabase Edge Functions (Deno runtime)
•    Node.js script via fetch or axios
•    Local PowerShell terminal using Node.js
Result:
•    405 Method Not Allowed
•    Response body: [empty]

What We've Tried:
•    Confirmed valid token and payload by copying directly from successful Postman request
•    Matched headers 1:1 with Postman (User-Agent, Accept, etc.)
•    Tested both POST and PUT methods
•    Ran tests from local machines, not cloud or edge networks
•    Confirmed /items endpoint works for creation in all environments

Please confirm if there are known restrictions for /items/{id} ?
Let us know how to safely send update requests programmatically 
Happy to share logs or tests if helpful.
Thank you! 
— Developer who loves Loyverse!