Autopairing fails intermittently

[Sean McAfee]

I started using autopair-mode a few months ago, when I'd finally had
enough of font-lock-mode coloring the rest of my buffer string-colored
every time I typed a quotation mark or apostrophe and paused for a
moment.  I'm fairly happy with it, but mysteriously, it occasionally
fails to pair up parentheses or brackets that I type.  It's totally
random, as far as I can tell; as I code, it just works or doesn't for
each opening parenthesis or bracket that I type.  Quotation marks are
always paired properly, however.

Also mildly annoying is that autopair-mode sometimes inhibits Emacs's
usual behavior of flashing the cursor back to the corresponding opening
bracket or parenthesis when the corresponding closing character is
typed.

Can anyone suggest a fix or workaround for these issues?