Placing dirt and torches. Dirt in main hand, torches in off hand. Looking straight down. Place dirt in hole. Click again to place torch, but torch not place. If item in main hand is non-placable like a sword or food item, torch places fine.

Placing torches on fence posts. Torch places just fine if in main hand. If main hand is empty, torch in off hand will not be placed on fence post. If main hand has placable object, will not place torch when main hand object cannot be placed but torch should. If main hand is a food item or tool, torch places.