I have, which is why I'm asking what is yet to be resolved or explained.
Auto update is not enabled on Linux
IF a linux client is automatically checking for updates, it is a bug
Basically as has been explained, it does not check online automatically, if it did then it is a bug and evidence would need to be provided.
Even the versions that do check online do not automatically update, they only prompt a new download and link to the website.
The "get pre-releases" check box only applies on Linux when manually performing an update check via Help > Check for updates