Then it shows the ignorance of the anti-evolutionists. A theory - by definition - is not fixed! It is a changeable, mutable, tested hypothesis that has not been proven as 100% fact. When that happens (like with mutual attraction of non-zero mass - gravity, or electron mobility in conductors - Ohm's Law) we call it a law.
To expect the theory of evolution to be fixed now and forever is to ignore the root word theory.
This is fundamentally the difference between science and faith; science is an approach, a process, and will see its fundamental tenets change over time because of discovery and testing.
Faith, on the other hand, may be "stressed" but ultimately is untestable as a concrete, tangible process or thing. It is what the believer wishes it to be, and there is no way to change that for it does not rest on observations, nor hard data.
So why do so many "evolutionists" say it's fact...no doubts whatsoever?
Darwin's original hypothoseis has been falsified by the fossil record. But the "theory" lives on.
Except for the tested part, you are right when you say "It is a changeable, mutable, tested hypothesis that has not been proven as 100% fact".
I would say say it's an evolving ever changing theory that has as it's guiding overarching primary principle that any changes to the theory must not by definition evoke an intelligent creator and must remain totally "naturalistic".
Intelligent Design is not based on faith.
It's based on observation, inference and logic.