Is accessing files via the mobile app causing your Docker container to crash?

Recommended to post this on the forum and see if anyone else is facing the issue. Info here: [Bug]: Opening a document on Android crashes the server (CODE-related?) · Issue #44821 · nextcloud/server · GitHub

Which Docker image, precisely?

There are multiple.

The image repository is linuxserver/nextcloud.

they have a separated support community. I would recommend you reach out to Support and Nextcloud docs