In section 2.3.5. State: Event Mode in the description of the fmi3SetClock function the following example is given as non-normative text:

[Rationale: a triggered output Clock c may depend on some variable v that is involved in an algebraic loop. As part of the iterations to solve the algebraic loop, v acquires a value that activates the Clock. If the final (or some intermediate) value of v no longer activates the Clock, then this Clock must be deactivated by the Importer during the same super-dense time instant.]

This means the importer has to call fmi3SetClock on an output clock. But calling fmi3SetClock is only allowed for input clocks.

Maybe it should simply be changed to:
"... then this Clock must be deactivated by the Importer FMU during the ..."