If you have an item in your main hand and then swap it with "F" key or your custom offhand slot key can trigger wardens/sculk sensors. However, swapping the item from the offhand to the main hand doesn't make vibrations.
Swapping items from your main hand to your off-hand would not generate vibrations.
How to reproduce
- Get any item and place a sculk sensor.
- Swap the item to your off-hand with "F" key.
- Notice how the sensor gets triggered.