I agree it's annoying that the car will not start/stay in iPedal as a default if that's the way you've been driving before reversing, parking, etc. I certainly wish that it did so and would encourage others to continue making noise to Hyundai about this minor but annoying shortcoming. That said, it does only revert to L3 (at least in my experience) which is the next best thing to iPedal and not dramatically different (as opposed to full-coast L0), so I think it's a stretch to say that it's a significant safety issue. If you consider it unacceptably dangerous then I'd suggest just staying in L3 all the time.
It may be that there is some drivetrain-related design issue that does not allow the car to go straight to iPedal from power-up, reverse, etc. I have noticed that sometimes in L3, shortly after driving away from the house, it will not allow me to switch to iPedal under certain conditions, almost always when I'm in the process of slowing for a stop sign or red light. The car displays a message about iPedal drive conditions not being met or some such. Rather than just being a stupid UI oversight to reset to L3 after reversing, etc., maybe that is happening because the car believes for whatever reason that iPedal conditions are not met then either. This still seems like a flaw of course, but it may be more complicated to fix from an engineering standpoint than many of us would wish.