ErrataRules Reference 1.7
The Rule Of Magnus: Magnet counters are now removed before the Magnetic card is revealed
Erratum
Should read: “Forced Response: After you place a magnet counter on this scheme, if there are at least 3 magnet counters here, remove 3 of them and discard cards from the encounter deck until a Magnetic card is discarded. Reveal that card.” (Magnet counters are now removed before the Magnetic card is revealed.)
— Rules Reference 1.7