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 linuxserver.io Support and linuxserver.io Nextcloud docs