Mixing with shapekey produces shapekey jumps on play/render

[hitrpr]

For me the natural way to use keymesh is mixing it with shapekeys to achieve smooth transitions and reduce work with simple inbetweens. But I`ve encountered issue, when I was making my first keymesh project

Here is videolog and explanation In short: at 1st frame of shapekey, where animation key is 0, it jumps to 1 instead, and on the previous frame keymesh frame do not appear (previous state instead).

You can launch animation from this file or render it to frames. keymesh-shapekey mix.zip

Here is my render result (2nd and 3rd are wrong, compare with viewport manual frame switching): FramesRendered.zip

[hitrpr]

p.s It would be great to have initial work with shapekeys. For example: while I use only deform tools, new key is just shapekey of previous shape. But when I start to change topology, shapekey bakes to shape and key become converted to actual keymesh. This will push animation workflow with addon very much! Simplier way — second button/hotkey, that creates shapekey with state [1.0] at current frame and key with state [0.0] at previous keyframe.