The 'Calculate from all levels <= player's level' leveled list flag may be missing on LL1NPCPotionsPoison3Strong [LVLI:0008DABA].
All of the other related PotionsPoison leveled lists have both the 'Calculate from all levels <= player's level' and 'Calculate for each item in count' flags on them:
LL1NPCPotionsPoison1Weak
LL1NPCPotionsPoison2Average
LL2NPCPotionsPoison10
LL2NPCPotionsPoison25
LL2NPCPotionsPoison50
LL2NPCPotionsPoison75
LL2NPCPotionsPoison100
While LL1NPCPotionsPoison3Strong has no leveled list flags on it. As it stands currently, once the player reaches level 10, the LL1NPCPotionsPoison3Strong leveled list will only ever yield 1x PotionDrainMagickaS "Strong Poison of Separation" [ALCH:00098466] for the rest of the game, which doesn't make a lot of sense.
As such, LL1NPCPotionsPoison3Strong [LVLI:0008DABA] may need to be evaluated on whether it should receive the same leveled list flags that match the related PotionsPoison leveled lists, potentially allowing for a greater variety of poisons to spawn from this leveled list, rather than just the same last one always.