More than likely the air bags are popping while being extended. If you put air in the air bags before you raise the jacks it should eliminate the popping sound.
Also be sure to retract the slides before airing up the air bags. Not that this has an effect on the sounds you hear but it is the recommended practice for our motorhomes. Other manufacturers may have a different preferred method but in our case retract, air up the air bags and then retract the jacks.
Gary and Kay & Chipper
2018 Thor Tuscany 38SQ
2019 Ford Ranger XLT Super Crew