It does not lead to crash (or not directly). Sorry if I wasn’t clear enough, I’ll try to explain it.
The function USplineComponent::GetInputKeyAtDistanceAlongSpline simply does not do what it says it does.
It should convert “Distance” values to “InputKey” values.
The second function (which works as it is intended) does the conversion because the input is Distance. It just converts it to InputKey, and then uses another function which expects InputKey. I just pasted it here to show that even if I miss something, I am sure that between the two function, one must be wrong.
Because the first says that in order to get InputKey from Distance Eval has to be called and the result has to be multiplied with “TimeMultiplier”.
According to the second the TimeMultiplier part should not be there.
According to my tests the second is correct.
As a temp. fix I can modify the GetInputKeyAtDistanceAlongSpline() return value outside, but that does not work in all case, because some part of TimeMultiplier is simply not accessible.