This is more specific to the Linux verson of BDS.  Many Bedrock servers, inluding my own, automaticly update the server by using shell scripts to check for the latest version of BDS, then download the updated software and update the server if necessary.  Since the release of the Preview version of BDS is on the same web page as the current versions, this caused many servers running BDS to inadvertently update to version 1.19.10.20.