If I triple-click to highlight a line or highlight the end of a line that appears in a checklist OR immediately before a checklist / checklist item, then attempt to apply a style -- bold, italic, heading level, etc -- the selection picks a random range inside my original selection to apply the style to. Only selecting the EXACT RANGE that I want to style allows the style to be applied.

There are a number of other funky style screwups that appear when working with bulleted lists and checklists, either independently or intermixed. Formatting drops, extra line spacing, extra dashes or bullets... here there be bugs.