The weight of a stack of arrows is calculated on load, not on stow/put. This is likely for performance - load always has RT but put/stow can be spammed with no RT. So you can create a stack of arrows with almost no weight, until you use them once.

I've never seen an issue where the calculated weight was greater than it should be. I think the proposed fixes here would be worse than the current implementation.

I've experienced the same thing. I can have 100 arrows weigh 50 stones, and that same 100 arrows can be 200+ stones and not fit in a quiver. It's definitely broken.

You count some broad-barbed arrows in your hand and see there are eighty-two left.

You are certain that the broad-barbed arrows weighs exactly 162 stones.
You are certain that the broad-barbed arrows are worth exactly 1500 Kronars.
Roundtime: 8 seconds.

stow arr in quiv
That's too heavy to go in there!