On Feb. 19, 2018, I worked on a document in InDesign CC 13.0 (Mac). I saved the document and all was good. Yesterday, March 28, 2018, I made some edits to the same document using CC 13.1 (Mac). But when a co-worker reviewed it, they noticed that the En Dashes (Unicode: 2013) I had used as a Bullet character had turned into a Russian glyph (Cyrillic Small letter Yeru, Unicode: 044B).

The bulleted section of the document was not revised between Feb. 19th and yesterday. The edits I made were in other sections of the document. Nor did I change the paragraph or character styles in any way or change the type face/fonts.

The other difference between the Feb. version and yesterday's version of the document in that I had installed the CC updates to InDesign: 13.1.

This seems to be a bug.