Annoying WiFi Issues with new MacBook Pro
For "mysterious" wifi connection issues, I have a blanket method that I do with any client Mac that has them, and it solves the problem in about 80% of cases, and in the remaining 20% of cases it is hardware.

So try this: Go to the folder 

/Library/Prefecrences/SystemConfiguration/ 


and remove the following files:

com.apple.airport.preferences.plist
com.apple.network.eapolclient.configuration.plist
com.apple.smb.server.plist
com.apple.wifi.message-tracer.plist NetworkInterfaces.plist
preferences.plist


You need admin to do this. Immediately after thrashing them, reboot. Removing these settings files will not 'mess' with your Mac in any, unless you have some very specific network setup you need to preserve, but doing so will in my experience solve many network hiccups.

If that doesn't help, one might suspect firmware or hardware problems.