Starbucks uses a captive portal for its free wifi.
This means that the wifi device gets an IP address, and data transfer does happen, but it is not what qgvdial wants.
The symptom is that when qgvdial attempts to make phone calls (or send texts or listen to voicemail), it fails to get the data in a timely manner.
0.2.383 released today is the result of about 2 hours of Starbucks wifi and sugary drinks. Hopefully it takes care of the Starbucks effect as reasonably as possible.