Assume a boat capsizes just before the finish line and drifts into the finish with the mast ahead and all crew still in touch with the boat.
The question is when the boat finishes – when the mast top crosses the finish line or when the hull crosses the line. — All boils down to the question whether the equipment (mast) is in normal position or not.
Definition ";" is "A boat finishes when any part of her hull, or crew or equipment in normal position, crosses the finishing line from the course side. However [...]"
Capsized is defined in ("A boat is capsized when her masthead is in the water.").
It can be argued that the mast is still normally attached to the hull and, hence, is in the "normal position" – and the rule only talks about "normal position" and not about, e.g., "normal sailing position". But still.
I was told that this has been solved in some old Q&A (such that it finishes when the mast crosses) – but as Q&A aren't kept when a new RRS is released, I cannot confirm it. Neither in the case books nor in the current Q&A nor in a 2015 printout of Q&A I could find anything. [Q&A E004/2015.011 had a similar case but focuses on the crew and only talks about the hull crossing the line.]