Comment 3 for bug 1460165

Found this: http://stackoverflow.com/questions/20365372/bash-completion-for-path-in-argument-with-equals-sign-present, where someone complains about this same problem and then they claim it was a broken completion script in their config. I moved away both the /etc/bash_completion.d/ and /usr/share/bash-completion/completions directories, to remove all completions installed in the system, and I still was able to reproduce the problem.

There's also the "complete" bash builtin, which establishes the behavior per command and for the default. However, changing the default as mentioned in one of the answers didn't fix the problem for me (not even after having removed all completions).