Ware the Hare has an SMG he experimented with. First he enchanted it with 2 Death damage, then tried an Oil of Cold with those enchants powered. It did the expected 9 Cold damage with 2 Supplemental Death damage.
After they expired (via death), the drop-down for powering the weapon still listed the override from the Oil, even long after it should've expired. It shows the durations as an ever-increasing negative number, until the enchantments are re-powered. Though that seems to just be an interface peculiarity, so I didn't make a post.
So he finished enchanting with an additional 3 Death damage a while back, and left one empty for Oil use. Never used another Oil. The drop-down keeps listing the override in order, after the first 2 Death enchants, and before the last 3.
Just today, he activated all the enchants to kill a ne'er-do-well he stumbled upon. Didn't use an Oil. He did 9 Cold, and 1 Supplemental Death damage per attack. Confirmed using the 'Back' button he spent the 3 AP and 9 MP to activate all the enchants. Back in the SH, with the weapon still powered, it claims it will do 9 Cold and 5 Supplemental Death damage.
On 1-2, he had killed another hoodlum. Checking the log, he apparently did 9 Cold, and 5 Supplemental Death damage per attack with the fully activated weapon. I didn't notice at the time that the damage type of the weapon had changed to Cold, honestly. Just noticed the correct amount of supplemental damage.
So, three (potential) issues:
Oil seems to stay as a permanent enchantment, which activates when activating all the enchantments. Haven't tried just activating the Oil override. Per the Wiki, it should just go away after the duration ends. But maybe the Wiki is wrong?
Possibly due to the order it was applied, it may be sometimes interfering with the activation of regular damage enchantments. Not sure about this; it's possible today's acceptable target Plum has Death soak via enchantments or something. There was no message about them soaking it, but not sure if there would be for supplemental damage.
The interface for Powering enchants is weird. It lists a negative duration as long as the enchantment isn't powered. But it doesn't show anything when it is fully powered.
And it lists the Oil override as an enchantment; though I guess that would be part of the 1st point.
EDIT:
Oooohay. Ware the Hare has since found himself in The Source, and gotten 'Strongly attuned to Flowing Time'. Which supposedly prevents enchantments from reducing over time. He activated enchants on a couple guns to test, including the above SMG, and they expired anyway. Another bug report to post.
But it seems to have fixed the Oil not expiring issue, since after a long time being stuck on the SMG, that has now worn off.
Per the time-stamps, they lasted 200 minutes. This tracks with the double duration effect of the regular 'Flowing Time' attunement. Never got the messages about enchantments expiring before this, by the way.- You focus your magical energies into your Sub-Machine Gun. With an audible thrum, you feel the latent enchantments powering it activate. You spent 9 Magic Points and 3 Action Points. (2025-01-14 10:18:21).
- You focus your magical energies into your Pump Action Shotgun. With an audible thrum, you feel the latent enchantments powering it activate. You spent 9 Magic Points and 3 Action Points. (2025-01-14 10:26:19).
- You place your Potion of Water-Breathing into your faction safe. (2025-01-14 10:26:52).
- (2 times) You sense the death enchantment on your Sub-Machine Gun go dormant. (2025-01-14 13:38:01).
- The Oil of Cold treatment on your Sub-Machine Gun has worn off. (2025-01-14 13:38:01).
- (3 times) You sense the death enchantment on your Sub-Machine Gun go dormant. (2025-01-14 13:38:01).
- (6 times) You sense the lightening enchantment on your Pump Action Shotgun go dormant. (2025-01-14 13:46:01).
I'd guess the 'Flowing Time' mechanic interferes with the Oil enchantment decay. Until you actually get attuned or strongly attuned, at which point the Oil decays.
Ware the Hare only attuned himself the once. But the game says it's strong attunement. Per the Wiki, that should be accurate if that was the last attunement used by any Conduit. But for all I know he could be under regular attunement, and the game interface is showing the wrong message.