This is a beta version, which by definition is a version released for testing. You should presume a beta version will have issues.
Comments and issues pertaining to the beta version are posted in a thread pertaining to that specific beta. This is where you will find the comments you are looking for. If you take a look at that thread, you will see a number of comments indicating issues with the aux switches. Not sure if your specific issue is in there, but it’s clear that there are problems with the Auxs in general with this beta.