Yes, it'll be using the 12 bit vars.
I just did a compile with the PC forced to use 12 byte vars, and that showed the problem too - so at least it'll be easy to debug
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Yes, it'll be using the 12 bit vars.
I just did a compile with the PC forced to use 12 byte vars, and that showed the problem too - so at least it'll be easy to debug