I figured out that functions.php was not the right file to edit. I added your temporary workaround to orgSeries-setup.php (the file you highlighted the conflict in) and the excerpts re-appeared. Yay!
The excerpt length box doesn’t appear to have any effect, so the entire excerpt displays regardless of the value entered there. It’s still an improvement, though, so I’ll take it. 🙂 Thanks.
Thanks for following up and the potential workaround. Does that code go in functions.php or somewhere else?
I tried it in functions.php and got the same result of no excerpt showing up after re-activating the OS plugin. As you probably gather from my question, though, I’m not a coder so I’m not positive I added that workaround code in the right place.