See the hotbar in my screenshot, the first command block cleared all items except the sword before executing /loot so you add other items up, there are 14 items in total.
No datapacks needed. I have investigated the source code, everything @FelixR said is right, mojang returned the number of stacks of items, not the total items.
Well, I commented in that issue but nobody paid attention to me...... nobody review my pr in the past two weeks......
I found this bug too and I fixed it. I want someone to review my PR at [github](Fix wrong redirect behavior by zly2006 · Pull Request #124 · Mojang/brigadier (github.com))
Well, hope someone can see this comment/my PR
I can provide another case that is used widely in technical MC community.
For this setup:
If I place the cart at the white wool, with minecart experiments turning off, the cart should be blocked by the amethyst, and then lose its velocity (eventually, the cart falls with no velocity, and will be burned by the lava in the cauldron). However, in the experiments, although it is blocked, it does not lose its velocity and keep moving forward.