docker – Sonatype Nexus doesn’t update single git submodule

I have this setup:

-a git repository called MyRepo. This repo has 5 submodules (A,B,C,D,E)

-a Jenkins instance that auto-builds MyRepo. On post-build steps there’s a simple script that executes:

#!/bin/bash
branch=$1
docker build -t server.com:5000/MyRepo:$branch .
docker push server.com:5000/MyRepo:$branch

-The server.com:5000 is the Nexus instance. Here all docker images are saved and can be pulled by docker-compose installations.

Now the problem is the submodule C (only this one) is never updated in the docker image. If I look the Jenkins workspace for MyRepo, the files are correctly updated.
The issue should be Nexus side, but I’m not sure where to look because it was configured by another person.
Is there any cache or something similiar? Are Nexus artifacts involved?