Sorry that I search for this old thread, but I got question and problem - I have GTasks on both my devices, phone and tablet, and when I add a task on my phone I don't see it on tablet. It doesn't sync between devices. Internet is on, GTasks set to auto and synchronisation is on.
Phone: SE Xperia Ray - Urushi | ROM: 4.4.2 Carbon nightly (20140222) | Kernel: 3.4.79-nAa+ | Baseband: 86 | smartassv2 - cfq / 245 MHz - 1113 MHz
Tablet: Samsung Galaxy Tab 2 7.0 P3100 | ROM: 4.4.2 PACman nightly (201400306) | Kernel: NEXT 220.127.116.11 | CWM 18.104.22.168 | interactive - sio / 300 MHz - 1008 MHz