I have two weapons: one have 1.40 attack speed and the other have 1.30 attack speed. If I remove both and reinsert (the same weapons) it changes my stats depending on the order.
To replicate the bug, here it goes:
1) Remove both weapons and put on your bag (or stash, doesn't matter)
2) Add the first weapon
3) Then add add the second weapon
So, if I add: 1.40 first then 1.30 second, my "Attacks per Second" becomes 1.72
But, if I add: 1.30 first then 1.40 second, my "Attacks per Second" becomes 1.60
Same weapons. Just remove and add.