Being rusty could lead to a couple issues. Without physically being able to watch you make a turn, I'll let you know what I've seen in the past 20+ years of teaching.
1. Equipment - you stated that your bindings came loose multiple times. So its time to start learning basic board maintenance. If its the same boots, and bindings that you've had when you felt "good" going edge to edge then you need to make sure all the straps are tight, angles are correct, and your boots have some life left in them. Ultimately its usually not equipment.
2. Rotational separation. IE your upper body is turned and your shoulders are not parallel to the board. This is #1 what I see for intermediate lessons / refresher lessons when people are having problems.
Your body's natural position is your chest facing the direction you are going... walking, sitting in your car, riding a motorcycle, EVERYTHING. So if you ride only a few times a year and then take a long break in between... this is super common. I mean test it, stand like you are on your board, turn at the waist and have your chest face the direction of travel and try and use your ankles to rock from your heels or toes. K Now just turn your head and keep your body in alignment with your board, IE waist and shoulders, just turn your head (that's what your neck is for) and do the same... 10 times easier right?
3. Lazy Stance - The longer people ride, the more they get lazy stance. Hell I still have to catch myself doing it. Simply standing over your rear foot and slouching into the back seat. The snowboard is turned from the front foot initiating flex to the edge and cutting into the snow, if you are standing on your back foot you have no weight to start the turn, the board will start to rotate (because it wants the weighted foot to be down hill) and then you catch an edge and blam...
Anyway, these are the 2 most common I've seen over the many years, they are nothing tragic, but they happen. Even some of the sickest riders have these tendencies in their riding, but if you watch them closely, they kind of "turn it off" right before they start a turn or set up for a trick of any kind.