You have made the correct ruling.
The Revived RoguesRogue's ability bolts from the grave, Bolts from the Grave, is decisively not a spell of 6th level or lower, thus the Rakshasa's limited magic immunity magic immunity does not affect bolts from the graveBolts from the Grave, as limited magic immunity onlylimited magic immunity applies only to
spells of 6th level or lower.