So far found on this one exercise, but there could be more... Not sure if it has anything to do with the fontdata.js not loading.
0.3.1beta3.dev2

I believe this may be addressed? cc @jamalex
I couldn't replicate it when re-running the pipeline locally. Let me test on the demo server and republish if necessary.
I've seen it this morning in the latest develop, sorry.
It's not actually a Kolibri issue, it's a content pipeline issue, so republishing and reimporting may fix it -- checking
If I recall well, it appeared when previewing exercises while creating Exam.
It'll appear everywhere the exercise appears in Kolibri, until the source content is fixed
Ok, waiting for re-publish to do the re-import!
It's got 3798 exercises to rebuild, which will take a while -- leaving it running for a while!
Had to make some additional fixes (https://github.com/fle-internal/sushi-chef-ck12/pull/2); running again now.
I'm guessing it did not finish building all - I just re-imported the CK-12 channel on my dev repo, but those strings are still visible:
