Intentional Spellweaver mechanic or bug?

Hello, been using Spellweaver and noticed something unusual, I’ve added on a creature fused with Runic Grimoire making my creatures gain the arcane buff, and a mimic with 3 spell gems equipped, when using the middle spell gem as Spellweaver, it seems to use up charges for the top and bottom spell gems due to the perk activating the top and/or bottom spells. Is this intentional?