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: 4.4.4 Carbon nightly (20140711) | Kernel: 3.4.95-nAa+ | Baseband: 86 | smartassv2 - sio / 122 MHz - 1017 MHz
Tablet: Samsung Galaxy Tab 2 7.0 P3100 | ROM: 4.4.4 Carbon nightly (20140829) | Kernel: NEXT 2.2.3 | PhillZ Touch 6.57.2 | interactive - cfq / 300 MHz - 1008 MHz