Wraith damage fluctuating on same target

[Lychwood]

My wraith went from doing 3 damage, to 5, then back down to 3 again, then back to 5 while attacking the same target. According to the log, all of the attacks were made dealing death damage and I can't see any reason in their build for why their death soak would go down, then up, then back down again. The player of the killed char is also stumped. Is it some kind of bug?

Seen on: https://nexusclash.com/clash.php?op=character&id=9344
Target: https://nexusclash.com/clash.php?op=character&id=1395

- (3 times) Your pet Black Lantern Bearer, a Wraith, attacked Instrument and hit for 3 points of death damage. You gain 5 experience points! His armor soaked 2 points of damage. (2022-06-19 22:13:21).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and missed. (2022-06-19 22:13:31).
- (7 times) Your pet Black Lantern Bearer, a Wraith, attacked Instrument and hit for 3 points of death damage. You gain 5 experience points! His armor soaked 2 points of damage. (2022-06-19 22:14:41).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and missed. (2022-06-19 22:14:51).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and hit for 5 points of death damage. You gain 8 experience points! (2022-06-19 22:15:02).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and hit for 3 points of death damage. You gain 5 experience points! His armor soaked 2 points of damage. (2022-06-19 22:15:22).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and missed. (2022-06-19 22:15:32).
- (2 times) Your pet Black Lantern Bearer, a Wraith, attacked Instrument and hit for 5 points of death damage. You gain 8 experience points! (2022-06-19 22:15:52).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and missed. (2022-06-19 22:16:12).
- (3 times) Your pet Black Lantern Bearer, a Wraith, attacked Instrument and hit for 5 points of death damage. You gain 8 experience points! (2022-06-19 22:16:42).
- Your pet Black Lantern Bearer, a Wraith, attacked Instrument and missed. (2022-06-19 22:16:52).

[Kandarin]

This is a previously undocumented feature of Wraiths. Once a Wraith has fully drained a target (zero MP) they get up to five points of Soak bypass vs that target. You can see that in the log - the wraith was affected by Instrument's soak, then drained them completely and thus ignored their 2 soak and hopped up to 5 points of damage. Then the AP tick happened and they got one attack worth of reprieve, then they got drained down again.

This is not a bug but ought to have been documented better, so it's now on the wiki.