EDIT: Fixed as of PC patch v5.0.5 (update 22)

If you have a weapon poison equipped on your frontbar, and proc your backbar enchantment whilst on this bar, the backbar enchant will inherit the item quality & level of the weapon poison (cp150, white-quality by default).

Backbar enchants can be procced on the frontbar via 2 ways:

1. With ground-based weapon DoTs (volley, ele blockade) that continuously proc the enchant of the originating weapon
2. Shoot a ranged light attack or weapon ability > swapcancel to frontbar > projectile connects with target

When this bug occurs, it results in proccing an enchantment effect of a lower value than normal. Typical poisons used by a max-level toon are cp150, white-quality by default, and your enchant's effect will be scaled-down to these stats.

Example:
You have a gold-quality, cp160 Berserker glyph on your backbar, which gives you +348 WD/SD when procced. If you use either of the two abovementioned methods to proc this on your frontbar, whilst having a poison equipped, you will only get +232 WD/SD—the precise value of a cp150, white-quality zerker glyph.

This also applies to enchants that deal direct damage (glyph of flame, etc.).