Why do some NPC's/beasts seem to ignore the fact I've just drank an invisibility potion (ie continue attacking me)

If I set my strength to 2000 using the console, why do my fully repaired weapons break after 2-3 strikes?

It sounds like you're drinking the potion after the enemy has spotted you ("continue attacking me"). It's a little late to try to avoid being noticed then. You should drink the potion before they spot you.

Your character's Strength stat has nothing to do with the amount of health your weapon has.

Indeed Strength doesn't affect weapon's health, but with that attribute on such high levels, the character hits so hard, that his weapons literally breaks in his own hands. Work the other way, too - barely anything will survive such mighty hit.

I think the amount o damage done by the weapon contributes to how much the condition drops on the weapon.

The higher your strength = the more powerful the blow = the more damage you do = the more your weapon deteriorates.

This is wrong. I have often used invisiblity potions to escape death mid-battle. Most of the time the attacker will simply stop attacking me. Sometimes though this doesn't work, hence my query.

Makes sense, thanks.