In the rule “Removal”, replace “If the named Cult has fewer Artifacts than the number specified, then the Believer loses 10 Insight (or, if they have less than 10 Insight, the Believer loses all of their Insight).” with:-

If the named Cult has fewer Artifacts than the number specified, then the removal fails and both the Believer and the Leader of that Cult are informed of the attempt’s failure (and the identity of the Believer)

Also replace “the Believer gains an equal amount of Insight” with:-

the Believer gains an equal amount of Insight; the GNDT update should indicate that this Insight was gained from Artifact Removal