Minions and equipping a sceptre that grants a minion skill

Guessing this is actually a bug (but one that I do like to use currently since my spirit is not that high yet):
When you equip a sceptre that grants skeletons at skill X and you have that skill at anything other than the same level (so higher or lower) it seems to grant 2 (spirit-cost) free skeletons at the level of the skill the sceptre gives.
When you equip a sceptre that grants the same level as you have, this does not apply/work and you effectively loose two skellies.

FYI: When stating "level" I refer to the base-level of your skill and not the potentially increased one by your gear.