My ASRock B450M-HDV that I've been using for almost a year now has always had this issues. When I first turn on the PC, it gets to the ASRock logo, and then freezes. I have to press the power button on my PC again within around 5 seconds maybe so I can get a normal shutdown, or else I'll have to do a hard shut down. When I turn it on again, it goes through easily. I've heard that it could be something with the ram timings, but I haven't dug that far into it.
Specs:
Ryzen 5 1600
ASRock B450M-HDV
8GB DDR4 Patriot Viper 4 Ram
R9 390X
Samsung 840 EVO 128 GB
WD Black 1TB
Specs:
Ryzen 5 1600
ASRock B450M-HDV
8GB DDR4 Patriot Viper 4 Ram
R9 390X
Samsung 840 EVO 128 GB
WD Black 1TB