Leaving Singapore and restricted stocks deemed exercise

[skeeting]

I'm considering leaving Singapore (and resigning from my employer). I understand tax clearance and withholding of salary and all that which is perfectly fine. What I can't seem to comprehend is the rule that any unvested stocks are taxed on departure. I'm curious to know or hear of any experiences with this because I can't seem to comprehend why there would be tax on shares that will never vest - e.g. if I resign from my employer, I am no longer eligible for the unvested stocks. Am I misinterpreting the deemed exercise rule? Thanks!