So after literally weeks of study and observation, I've noticed that after a fresh install, my phone tended to maintain connectivity after calls. As time went on, the data connectivity became hit or miss until finally I had to toggle airplane mode on and off after every call. On a whim, I rebooted into recovery, wiped my Dalvik cache 3x, and rebooted. Just as with the clean install, my data connectivity was uninterrupted, coming back on immediately upon hanging up from the call. Intrigued, I repeated this process time and time again, and I've seen the exact same results every time. Wiping the Dalvik cache eliminated connectivity issues for me, but after three-four days of solid use, my phone goes back to needing to be toggled in and out of airplane mode after every call. A programmer I'm not, so this could merely be complete coincidence; however, if this does help one of the talented devs do something along the lines of a more permanent fix, that would certainly be great.