When charging a weapon, you get an estimate of how many charges it will have per full recharge (how many times you can use it before all the charges are depleted). For my character, a super fun combination of Absorb Health + Fiery Soul Trap, the # of charges is about 170. If I save, close and start the game and reload, the number of charges per recharge is decreased tenfold. Decreasing my Enchanting skill makes the effect less pronounced (down from 50 charges to 25 charges). Enchanting another weapon with similar enchantments fixes the issue until the next restart.
Elderscrolls Wikia mentions the bug in passing, but offers no solution:
(PC) When editing your enchantment level to a high number 200+. Enchanting an item at max enchantment stats will cause the item to have 0 charges when made but under certain circumstances the effects will still be applied as long as the game is not terminated. (e.g. Absorb health + Fire damage on a sword) Once the game is restarted the items will lose their charges and will not be rechargeable.
Is there any way I can fix this, other than making a custom enchantment with 0 cost in CK?
I am running the latest version of Skyrim (1.7.7.0.6) with Dawnguard, I have disabled mods to test the issue and it persists.
