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 (20140325) | Kernel: 3.4.82-nAa+ | Baseband: 86 | smartassv2 - noop / 245 MHz - 1017 MHz
Tablet: Samsung Galaxy Tab 2 7.0 P3100 | ROM: 4.4.2 PACman nightly (20140420) | Kernel: NEXT 2.1.9 | PhillZ Touch 6.21.2 | ondemand - sio / 300 MHz - 1008 MHz