The helpful comments by @TianxiangXiong and @phils identified the problem: ESC is the prefix char for M, so emacs will be confounded by the keybindings I've given it. This is a pity since I really wanted those shortcuts. However, based on this commentthis comment, I was able workaround this and get what I wanted by simply changing ("ESC" . company-abort)
to ("<escape>" . company-abort)
in the :config
. At least in my system (Ubuntu 16.04) this worked.