Invisible Armor Stand with Item Bug

When you give an invisibility effect to any armor stand with /effect command while holding an item, the item is having issues, sometimes the item follows the player, sometimes it is transferring to another armor stand. The item is not connecting to the armor stand as far I see. I just wanted to make a floating item effect with armor stand for my map, but this bug is happening.

Also, I'm testing on the classic world, no experimental features, no Education Edition features, etc.