dockerfile COPY not copying file

I’m creating a dockerFile and trying to copy an environment configuration file that I’ve at the same path where dockerFile is found. The idea is to copy it during the docker build process to be able to use it during the gradle build a few steps later.

RUN 
  set -ex && 
  cd /app/src && 
  git clone URL.git  dest_folder

COPY .env_dev /app/src/dest_folder

After that, to check if the file is already there I make a pwd to ensure I’m in the right folder and ls -la to see if the file is there, but it never is, I can only find files downloaded from the repository, but of course, the .env_dev with credentials is not uploaded to the repository.

RUN 
  cd /app/src/dest-folder && 
    pwd && 
    ls -la

I’m sure it may be something tricky I’m not using correctly but checked with both ADD/COPY with no results. I’ve even tried to use the wrong filename to see if COPY complains about it, and it does, so … it seems that COPY finds it.