A follow-up to 0.17.0, found while sweeping a real course after its repair.
Tapping a glossed word now always explains that word. One rebuilt course had a section where nearly every tap showed the explanation of a different word. The reading builder now verifies that each highlighted word points at its own explanation, retries a rendering that gets this wrong, and as a last resort the affected words are served without a gloss instead of with a wrong one.
Explanations fit every form of a word. A word that appears in several forms shares one explanation - it is now written for the base word instead of locking onto whichever form happened to come first.