The rebirth system only awards points when the combined level of your characters exceeds the highest accumulated level you've previously reached (e.g., a total of 5 levels = 5 points; then, a total of 6 levels = +1 point). It is true that the system is slow and needs improvement (something I'm already working on) but it isn't bugged.
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UI says "You will gain 31 rebirth points." I Click REBIRTH!, it resets, interface has switched to Spanish, and I have 0 rebirth points to apply to the rebirth tree. This looks like a hard reset. Also, the game does not seem to save after closing. I do like the gameplay, interface, and graphics, but something seems broken on my build (Playing on Chrome).