Serverless AWS Lambda Function update criteria


I am using Serverless in AWS and I have a question regarding the behaviour of updating functions (or not).

Just a question about how Serverless (namely, version 1.40.0) works regarding deployments.

I have 3 functions defined in my template and I am using serverless-python-requirements, serverless-pseudo-parameters and serverless-prune-plugin plugins. I should say each function is packaged separately .

I added a new function to my template and did not change any code or configurations from the previous 3 functions . I was expecting (probably in a wrong way) that the previous 3 functions would not be updated (meaning a new Lambda version would not be created) but that is not the case. This pops some questions in my head (according to this behaviour and Serverless documentation):

Thank you in advance.