Hi. 20190502-1 is already outdated, since amdgpu firmware had some updates upstream: https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/log/amdgpu
Does this problem still occur if you use latest upstream firmware? By the way, it works well for me (Ryzen 7 2700X / Vega 56), but I'm running kernel 5.2.1 in Debian testing. Best regards, Hillel Lubman.