If the board is moving a bit from side to side, that is okay and would not affect the ProVari's function.
If the board is moving up and down, that is another issue.
To find out which type of movement you're getting, would you be willing to look at the display head on through the window without the battery inserted and push the button a few times? What does the PCB do?
Next, insert your pinky and move the PCB while looking at the display. What does it do?
And lastly, insert the battery and screw the end cap in place and push the button several times while still looking at the display. What does the PCB do in this case?
If you could let me know the answer to these questions, I can further assist you in figuring out what exactly is wrong and what can be done
More than likely, the movement you're feeling is the battery. Pull up on the spring in the end cap to stretch it out a bit, maybe an eighth of an inch or more. Make sure and hold the bottom of the spring so it doesn't pop out of the end cap. They're a pain to get back in. This will help secure the battery into place and provide a more solid connection.
Please let me know what you find.
Best Regards,
Kim