THERE IS NO SUCH THING AS
Optimise - Verb. make perfect or complete; "perfect your French in Paris!"
Optimisation - Noun. the act of improving something; "their improvements increased the value of the property"
Therefore, by definition, it is impossible to "over" optimise something as you cannot make it more than perfect or in excess of 100% complete.
This lesson was brought to you by the common sense of Paul Martin. You're welcome.