Note : Going to start with hitting things that are obviously implemented wrong and search for outliers later.
1. The property "hit curse" should not spawn on weapons and should not be reforgable. It only comes on specific artifact drops.
2. Damage Increase ; 1(5)-25% on jewels, 30% and 35% on powerful items. [I have not seen any of these spawn in anything other than increments of 5% post magic item generation system.]
2a 1(5)-35% on shields
3a 1(5)-70% on weapons
3. Durability bonus on reforged items - Should be tagged "+% durability" so that a crafter can identify a property used and weight taken from the item.
4. Items named "Charmed / of Alchemy, Vicious / of Slaughter, Auspicious of Fortune, and "Towering / of Aegis" are EXTREMELY rare, just as you cannot craft these named items with too powerful a kit, the more powerful the item the more rare these names should be. These attributes are more often found as "unnamed" items which take random properties from different branches.
5. Hit point increase should not be a property found on jewels as loot.
6. Stamina increase has a range of 1-5 on jewels and 1-10 on armor.
7. Mana increase has a range of 1-5 on jewels and 1-10 on armor.
8. Dex increase has a range of 1-10 on jewels and 1-5 on armor.
9. Str increase has a range of 1-10 on jewels and 1-5 on armor.
10. The negative property -100 Luck was removed years ago, having trouble finding the exact patch.
11. Luck items from the magic item system comes in increments of 10 up to 150.
12. Reforging items for luck with a spined runic is supposed to be very easy to get a 150 luck piece. Here it is probably / nearly impossible.
13. Reactive paralyze should never be found on a ranged weapon. [You cannot parry with ranged weapons to use it.]
14. The property "-1 faster casting" does not, and has never existed. It is the side effect of "spell channel," not a negative property, and therefor should never spawn without spell channel.
15. Splintering weapons should be 100% intensity at 20% - 25% and 30% are overcapped powerful items. The frequency of finding 25%+ splintering weapons here suggest that is not currently the case.
16. Hit point regen is not found on jewels.
17. Stamina regen is not found on jewels.
18. Swing speed on jewels is 100% intensity at 5%, with 10% being overcapped.
19. Negative properties on items are supposed to increase that items power by a factor of the disadvantage.
Example ; Brittle and prized items should be moderately more powerful items - Cursed items should be MUCH stronger.
20. Spell damage comes in 1% increments until 12%, + 15%, 18% when on powerful overcapped items.
21. Talismans show property orders wrong.
Im sure there are a few more, will take another look into item properties once these are fixed. If you want to ignore the crafting related ones I can make a seperate post with those.