Strange stepper issue

I had a strange issue and I'm hoping it'll mean something to someone so I'll know how to avoid it in the future.

I have a machine running four steppers with four DQ856 drivers made by Wantai.
I swapped one of the drivers for a DM556T made by "Stepperonline".

Power supplies are Meanwell 48V switchers . With the original DQ856 there's no issues but with the DM556 set to the same exact settings (5.6A peak, half idle current, 3200 pulse/rev) it still seems to work fine, but the motor feels like it's twitching if you hold it in your hand and it slowly gets warm over time. With the DQ856 there's no such behavior, it feels completely dead when idle, but is locked like it should be.

Is there something wrong with the DM556T driver? Is it because I'm running it at 48V and it's rated for 50V max? Is it just because it's a cheap driver and I need to stick to better quality ones? I'm assuming the Wantai ones aren't anything to brag about either.....