Bug? Find facility unreliable

Twine Version: 2.6.0.0

I flag branches that still need to be done with TODO!!! in the main text of the passage. Then I can just do a find on that and quickly see where I still work to do. Except… it does not always find it.

The game I am working on has one passage (that I know of!) flagged as such. In fact, even if I just search for the letter T, which is in the passage three times, it fails to find it.

This is case insensitive. If I have it search the title, it does highlight the passage - it can find the T there.

There are no links to or from this passage, but I have other passages like that that it successful find. It has two bits of SugarCube mark up, but I have virtually the same elsewhere - though this passage has no text besides that.

A bit of messing suggests there needs to be a minimum length of text before the find facility will both to look. Not sure exactly what that is, but more than 20 characters.

Has anyone else experienced this? It is a worry because my TODO tactics seems inherently unreliable now.