Problem in simulation results in PSPICE using LM3880 sequencer
I’ve never used an LM3880 for power sequencing.

I have however used a Silego Greenpak, programmed for my specific needs, and got reset and other functions in the bargain. I’ve even used one to make an LPDDR4 sequence, which is very fussy about power up and power down.

If your regulators have PGOOD flags, then you don’t even need that - diode logic is more than good enough, and absolutely predictable.