I would suspect it’s still the voltage. That’s important since everyone complaining about power problems is asked “how much is your PSU rated?”, then they answer “2A” and will be advised to go with 5V/3A (USELESS since the shitty connector isn’t able to exceed 2A and only rated for 1.8A).
Sometimes these ‘stronger’ PSU seem to work. But most of the times this is due to a better/different cable between PSU and board and not the more theoretically available current
This is already general knowledge for boards that can’t exceed 2A in consumption (like Banana Pi M1). The M3 when running under full load with good heat dissipation, a few USB peripherals and a connected disk might easily consume 3A. Using micro USB here is just moronic.