I don't quite know where to report this bug, but if you select a string of text that includes a substring that is identical to another substring in the same paragraph (but not currently selected), then requesting a highlight will actually highlight the FIRST substring in the paragraph and then the remainder of your selected text rather than your original (full) selection.

Example:

.... [1] the fox jumped over the [1] box.... [2] the fox jumped over the fence [3] even though the fence was tall. [3][2]

If you select the string between [2] and request a highlight, it will actually highlight the string between [1], and then the string between [3].