Thank you for the data.
Those temperature values come from the driver and Polaris GPUs are not expected to return additional temperature values (like Memory, PLX and Liquid). So this is most likely a driver bug.
If HWiNFO was showing a discrete GPU VRM sensor and now it doesn't you might try to reset the GPU I2C Cache in HWiNFO. If that won't help, it's also likely that the new driver blocks access to the VRM.