If you want to travel outside Australia for any reason while you’re waiting for your Partner Visa to be approved, you’ll have to apply for a Bridging Visa B (subclass 020). When granted, this visa will supersede your Bridging Visa A (with the same work/study rights) and may remain active until your Vasa is approved— but it still doesn’t mean that you can enjoy unlimited travel outside Australia. Your Bridging Visa B comes with a limited travel period based on the dates you requested and the information you provided in your application.
You might also be granted different entry rights with your Bridging Visa B. Some BVBs will allow multiple entries within the specified travel period, meaning you can travel in and out of Australia as much as you want, while others will only permit a single entry, meaning you’ll need to apply for a new Bridging Visa B if you want to leave Australia for a second time, even if it’s within the travel period. If you really need a long travel period or multiple entries on your BVB, you should specify this in your application and provide appropriate evidence to support your request.