I've installed 19.9.3 drivers and switched back to PM 4.7b from claymore's miner, now mixed rig is working flawlessly, thank you @PhoenixMiner. BTW claymore's miner consumed 10 watts less and hashrate was just 0.8 MH/s lower for RX 5700.
Any significant improvements?
For me PM always was better, but previous version was unstable with 19.9.1 drivers and with 19.9.2 didn't work at all. Now it looks like stability problem solved, however i see one reboot during last night. Also i've noticed that 5700 card after some time begins to give +2 Mh/s, but after dag switching this speedup is gone and again after some time miner shows +2Mh/s until dag switch.
I updated everything shortly after posting to see for myself. I figured that I could always revert back.
I can say that it seems less stable in my experience.
I didn't have any reboots (maybe one every three days or so) but since the updates my miner crashed slightly more than usual. Crashes (not reboots) at 11:53pm, 1:57am, 6:26am and at 9:10am.
No reboots yet. I can't explain the crashes, I didn't do anything but install the updates. I'm considering on rolling back the drivers.