Hmm, have you tried with more than one WiFi connection?
Sent from my HTC One_M8
Example:
ro.carrier=wifi only
ro.carrier=unknown
Changed example:
ro.carrier=wifi only
#ro.carrier=unknown
If anybody can confirm this makes a difference or not please post results
EDIT::
After two weeks without problem anymore it appears the fix was the static IP address not the build prop change.
I found threads going back to at least 2007 about Samsung devices having trouble with dhcp and all the solutions being manually assign a static IP to the device.