## TL;DR

Creating a bucket on Tigris with LocationConstraint=iad returns success but silently creates a Global bucket instead of an iad-region bucket. iad is not an AWS-defined location constraint, and Tigris was accepting it and discarding the placement requirement without any error.

## Steps

1. Creating a bucket on Tigris with LocationConstraint=iad returns success but silently creates a Global bucket instead of an iad-region bucket. iad is not an AWS-defined location constraint, and Tigris was accepting it and discarding the placement requirement without any error. The risky behavior is the silent fallback: callers got success while their data-placement requirement was ignored.

2. Fixed and deployed by the Tigris team: the unsupported location constraint is no longer silently dropped. If you are pinning data placement, verify the bucket's actual region after creation rather than trusting the successful response.

## When to use

You are seeing this: The risky behavior is the silent fallback: callers got success while their data-placement requirement was ignored. Use this skill when you run into "Tigris: CreateBucket silently falls back to Global for LocationConstraint=iad".

## When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

## Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

## Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.