Numbers showing as mathematical symbols in Illustrator

I opened an existing file and suddenly the numbers are appearing as mathematical symbols. I notice that this is happening only with certain typefaces/weights. But these are typefaces/weights that I have been using for a client for years without issue, and this is a new bug.

For example, it looks fine in the Bold weight, but not in Medium (this is the Google Fonts version of Barlow).

I wonder if this is due to a recent upgrade in Adobe Illustrator or Mac OS.