The first two studies described have roughly the following form: 1: The researchers tell the students "X is true". 2: The researchers tell the students "state

The first two studies described have roughly the following form: 1: The researchers tell the students "X is true". 2: The researchers tell the students "statement 1 was a lie". 3: Many students report they still believe X is true. It seems risky to read anything much into that. Maybe at step 3 the students, who know they've been lied to at least once, were reluctant to assume that step 2 provided reliable information.