AWS Lambda Function using container image - reference by tag, not digest

Hi there

I would like to clarify something in the documentation here : Serverless Framework - AWS Lambda Guide - Functions

It states that we can reference images using repository@digest or repository:tag formats. However, when i try to use the tag format i get an error:

Configuration warning at ‘functions.xxx.image’: unsupported string format

Environment is:

Your Environment Information ---------------------------
Operating System: darwin
Node Version: 14.17.5
Framework Version: 2.57.0
Plugin Version: 5.4.4
SDK Version: 4.3.0
Components Version: 3.16.0

Is this my misunderstanding, a documentation error, or a bug?

Many thanks in advance everyone…

Chris