Emacs sporadically gets into a state in which M-q wraps lines at apostrophes

[Matt McClure]

My Emacs sporadically gets into a state in which M-q wraps a line with
apostrophes like:

    it's a test
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

as:

    it's a test
      'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

rather than:

    it's a test
    xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

I added the white space indentation added for readability above. It's
not in the actual text.

I'm using: `GNU Emacs 24.1.50.1 (x86_64-apple-darwin, NS
apple-appkit-1038.36) of 2012-06-10 on bob.porkrind.org`

I've customized adaptive-fill-regexp, in case it's relevant to:

    "[  ]*\\([-–!|#%;>*·•‣⁃◦0-9]\\.?+[  ]*\\)*"

so that lines beginning with a number optionally followed by a `.` will
wrap with a hanging indent.

I notice that the value of adaptive-fill-first-line-regexp is:

    "\\`[       ]*\\'"

I'm suspicious of its including `'`, but changing its value by
removing the `\\'` doesn't make the text wrap as I expect.

Quitting and restarting Emacs makes the text wrap as I expect again.

I haven't been able to find the relevant difference in Emacs's state
before and after I restart to isolate the issue or prevent M-q from
wrapping at the apostrophe.

Where should I look next?

-- 
Matt McClure
http://www.matthewlmcclure.com
http://www.mapmyfitness.com/profile/matthewlmcclure