There is nothing in DT that would affect X or key mappings, and in fact, I've run a couple of tests with xev first and xbindkeys later and found no repeated key events, as expected.
xbindkeys is very tricky with its xbindkeysrc file format, and any error like a missing/extra space means both scripts get executed at the same time, producing the observed behavior.

By the way, a simpler and cleaner way to achieve the same would be this .xbindkeysrc