I just checked in the sources, and downloaded and tested the released CLS2Sim 4.14 from our website.
It is using true airspeed and is not affected by pitot failure.
You’re on the newest X-Plane?
@hamsammich: Did I give you a prerelease/beta using indicated airspeed? (The version number would have a b at the end.)
I’ll contact you and we’ll have a look at it.