lit: classList wierd behavior for dynamic key

[codart1]

Describe the bug
I made a small sandbox that reproduces the issue here: https://codesandbox.io/s/solid-class-list-bug-otwqz

Try to click the button a few times and observe that the output classes are incorrect. It should only be haha foo or haha bar. Not haha foo bar.

[ryansolid]

I see it. I'm not passing previous values into classList or styles bindings in the lit version of Solid.