Can the artificer’s spell-storing item affect a Rakshasa?

My character is being hunted down by 3 Rakshasa. The character is aware they possess limited magic immunity which reads as follows:

Limited Magic Immunity. The rakshasa can’t be affected or detected by spells of 6th level or lower unless it wishes to be. It has advantage on saving throws against all other spells and magical effects. [Basic Rules, p. 341]

As a level 11 Artificer, I can store spells into a Spell-Storing Item.

Spell-Storing Item

At 11th level, you learn how to store a spell in an object. Whenever you finish a long rest, you can touch one simple or martial weapon or one item that you can use as a spellcasting focus, and you store a spell in it, choosing a 1st- or 2nd-level spell from the artificer spell list that requires 1 action to cast […].

While holding the object, a creature can take an action to produce the spell’s effect from it, using your spellcasting ability modifier. […] [ERLW p. 58]

Since the item is just "producing the spell’s effect" should it be treated as a magical effect instead of a 1st or 2nd level spell?

Is the Rakshasa immune to the spells produced by the item? Or would they just have advantage against saving throws?