Hi Benjamin!
Thank you for your question. I can confirm your experience. The parser emits an error similar to:
"java.io.IOException: IllegalArgumentException: net.sf.jsqlparser.JSQLParserException JSQLParserException:" ... Encountered: "&" (38), after : "
So this operator looks like it is not implemented yet. We will let the team know.
In the meantime, maybe try the query through our datalab command line client, or the API? For the filters it's convenient to have bitwise logic available, but a workaround sometimes is easy just using decimal ranges.