When "Update Rate Optimization" is enabled In Skeletal Mesh Component, "Anim Curve" results are not as expected

You may actually need the value at the current time right now, but im willing to be that eventually you’ll need the value at a custom time.

So you may as well break into the source, extract the function / keep it open to peek at it, and code up a costum function to get your value out at the time you query for.
Expose it to BP or what not (it’s always faster to just use c++) and that should get what you need - while going around this possible bug, if you query the animation directly.