Pipeline conflicts with user AWS configuration

I’ve got a default AWS configuration at $HOME/.aws/config which includes the following:

[default]
region = us-east-1

This causes Sarek to fail when it’s trying to download the iGenomes data. The error message is:

The authorization header is malformed; the region 'us-east-1' is wrong; expecting 'eu-west-1' (Service: Amazon S3; Status Code: 400; Error Code: AuthorizationHeaderMalformed; Request ID: EFD0047C3BC01410; S3 Extended Request ID: MMiKH3WnN3XQ8ZdtQN48D6lriG36JRv7cbMm5yuNv8cNqHpwhfB5XFUJvZt4pY6qX1ZsOQoPGMg=)

-- Check script '/home/konrad/.nextflow/assets/nf-core/sarek/main.nf' at line: 268 or see '.nextflow.log' file for more details

Removing the default AWS profile fixes the issue, but should not be necessary: Sarek should explicitly set its own AWS profile (including a region) to avoid conflicts with system profiles.

(This is using Sarek at rev b952fe2b3fcd3541237c9f4a9f27e1852f537967 with no user configuration, launched as nextflow run nf-core/sarek --input samples.)

Reproduce the failure with nextflow run nf-core/sarek --input samples while $HOME/.aws/config sets region = us-east-1, then inspect main.nf at line 268 and .nextflow.log. Trace how the iGenomes download selects its AWS region or profile. Done means the pipeline downloads iGenomes without requiring removal of the user's default AWS profile.