I am running version 1.8.2 without docker or XMR, the clients are windows based and the collect interval is 5 minutes. What I am experiencing is that when I replace media I can see the change when looking from ‘Design’ or ‘Preview Layout’ view but the clients do not always reflect the change.
1.8.2 is an older version of CMS and many issues have been fixed since that release, I would first recommend upgrading your CMS to 1.8.13, which is the most up to date version of 1.8 CMS. Does the issue still occur after the upgrade?
Just in case, here are links to the upgrade guides for Docker and the Blog post for 1.8.13 where you can download the CMS files you will need: