1:
1x Found spell 'Necrotic Venom' using id 215449 on 16, tell the authors!
BigWigs_Core\BossPrototype.lua:1136: in function UnitDebuff' BigWigs_Legion\Nightmare\EleretheRenferal.lua:132: in function ?'
BigWigs_Core\Core.lua:59: in function <BigWigs_Core\Core.lua:54>

Locals:
InCombatSkipped

2
1x Found spell 'Mark of Ysondre' using id 203102 on 16, tell the authors!
BigWigs_Core\BossPrototype.lua:1136: in function UnitDebuff' BigWigs_Legion\Nightmare\Dragons.lua:212: in function ?'
BigWigs_Core\BossPrototype.lua:450: in function <BigWigs_Core\BossPrototype.lua:416>

Locals:
InCombatSkipped

This belongs to https://github.com/BigWigsMods/BigWigs_Legion

Still seeing these, plus this one:

1x Found spell 'Mark of Emeriss' using id 203125 on 16, tell the authors!
BigWigs_Core\BossPrototype.lua:1141: in function UnitDebuff' BigWigs_Legion\Nightmare\Dragons.lua:212: in function ?'
BigWigs_Core\BossPrototype.lua:456: in function <BigWigs_Core\BossPrototype.lua:422>

Locals:
InCombatSkipped