Google Cloud Storage - Public object with cache-control "no-store" still stored

I'm trying to upload a file that change every few seconds on google bucket. File is public readable, so if I not pass a cache-control value, file is automagically cached.

I'm pushing file on storage with gsutil from inside a bash script, like this:

gsutil cp filename.ext gs://bucket/directory/filename.ext && gsutil iam ch allUsers:objectViewer gs://bucket/directory/filename.ext 

Then update cache-control with this code:

 gsutil -m setmeta -h "Cache-Control:no-store" \
         h "Content-Disposition" gs://bucket/directory/filename.ext 

My file is not cached first times i call it, after few calls file being cached.

On google cloud, file actually has no-store parameter enter image description here

I can't use inside URL that calls the file parameter to prevent cache (parameter like noCache=1 -> don't remember the exactly parameter, but in this case can't use it)