enchantments work incorrectly if custom attributes are applied

(lacking time so did not have in-depth tests)

Today i was testing out new minecraft 1.16.1. Usually i first create an OP equipment set in my world, this time with newly-introduced item attributes. But when i try it out, something not quite right happened:

I have a netherite sword with lvl10 smite, lvl10 sharpness and lvl10 bane of arthropods (simultaneously via command block) and struck good hits on a wither boss. But when i turn toward non-undead mobs, it take way more hits to kill, which was not the case in previous version.

This could mean 2 things: Smite enchantment overrode Sharpness and Bane of Arthropods (again, not the case with previous version), but this may or may not be intentional. Or, maybe it was the attribute

I then tested with "attack speed" attribute +2 and only level 10 sharpness

+The lvl10 sharpness kill a strider in just 2 hit

+The lvl10 sharpness AND +2 attack speed kill it in 3 hit. All consistent. Which, should not be since attack speed has nothing to do with damage

TL;DR: Either stacking same type of enchantments, enchantments with higher-than-survival-possible, or item attribute is not working right

Ways to reproduce:

1/ get a sword with sharpness x:

        /give @p netherite_sword{Enchantments:[{id:sharpness,lvl:10}]} 1

2/ get a sword with sharpness x and +2 attack speed attribute  

     /give @p netherite_sword{Enchantments:[{id:sharpness,lvl:10}],AttributeModifiers:[{AttributeName:"generic.attack_speed",Amount:6,Operation:0,UUID:[I; -120526,22951,162125,-45902],Name:"generic.attack_speed"}]} 1