There's a related issue being discussed in another support thread but I decided to create a new topic to describe a single issue and observation.
Let me jump right to it...
When you say "Alexa, Set the Fan to High", she sets the Fan to 100%. The Fan doesn't respond and Alexa responds with "The device is not responding".
The HE log shows the following for Amazon Alexa Skill log
2019-08-08 08:27:33.227 pm traceSetPowerLevel 100
and the following for the Fan log
22019-08-08 07:52:28.445 pm warnunmapped value:null
The same issue doesn't occur when instructing Alexa to set any of my GE Z-Wave or GE Z-Wave Plus Dimmers to High. The are configured with the Generic Z-Wave Dimmer and Generic Z-Wave Smart Dimmer types. The Echo Skill Log shows the 100% coming in and the device log show the device being set to 99%.
I further troubleshot the issue by configuring the fan to use the above dimmer device types and additionaly tested with Botched1's GE Z-Wave Plus Fan Control. In all cases the fan responded to the High request and Alexa responded with OK.
So this is why I think the issue may have something to do with the device type not handing the 100% correctly.