Well unfortunately I am not the only person wanting to have Shape keys that work differently.
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In your blend file you start with Key1 and keyframe the value to 1
Then you move to Key 2 and keyframe the value to 1.
Leaving two shape keys with a value of 1.
In my experience shape keys will not produce a good result in V3D if the your shape keys have more than one value set to 1 at one time.
You may want to try key framing key1 to 1…then a few frames later, set Key 2 value to 1 and set Key 1’s value to 0 and insert a keyframe for both. This way the shape key moves from one position to another cleanly.
Here is an example…with shape keys animated with only shape key having a value of 1 and the same object with shape keys where there are more than one shape key value keyed to 1.
https://v3d.net/sso
project file and blend file: https://v3d.net/ssp
Hope this helps.