After upgrading to 7.20.X, and 7.21.X
Issues:
1: usb devices like usb dongle acting weird, losing connection frequently, i have multiple usb dongle connected to hex
2: usb device sometimes not comming online
3: winbox crashing frequently
4: high cpu usage, cpu temperature 75C at idle
5: checking system resource hardware usb, cause winbox crash and cpu raise to arround 100%
Note: Downgraded to 7.19.6 works fine.