iterm2 reopen
ITerm2 2.1.1 OSX 10.9.5 Build 13F1066
I'd love to accommodate with the plist file, but I'd have to trash my configuration to wipe various commandline strings which appear in it. Outside of the many console configs for connecting to a variety of devices, it's a pretty basic config. I do have dual monitors, but this presents even when I boot with only the integrated display.
The issue is simple: in Mavericks (OSX 10.9), the OS will restore windows when you restart. EACH time this happens, Iterm2 gets one column wider. 80x25 restarts as 81x25, and unless resized, the next restart brings it up as 82x25, and it continues. I expect the issue may relate to the additional space used by the scrollbar not being considered when the window is initially restored.