This is just a public service type deal, if you arent aware of this bug you might be costing yourself some spellpower, if you are aware you can regear as a workaround.
When tbine changed the random loot spellpower implement bonus wasnt done right and so it was all over the place and possibly very high, for whatever reason to "fix" it they seem to have put max bonuses based on the lvl of the item rather address the math errors in scaling.
Due to this, on random loot any spells or enhancement that add to weapon enhancement bonus that previously would add +3 each to implement spellpower bonus no longer do, luckily it still works on named items(or at least all of the named items ive tested).
Examples of thes weapon enchantment bonuses for any that dont get what im saying are magic fang spell(very large potential spellpower boost for some), stalwart defenders shield expertise enhancement(+3), Enchant weapon spell(+1) and Harper enchantment enhancement(+1). These are just the ones ive tested, there are likely more, cant remember.
So basically, make sure you use a named spellcasting implement(even a shield) if you use any of these and want the implement bonus to scale correctly, if you are a druid or druid multiclass it can cost you 30ish spellpower if you dont.