Game skipping last wave on Hard

[Kos023]

I don't know if this happens in other difficulties as well, but I have devised a maze that takes me through Hard without losing one life or juggling, but I found out that if I don't send the last wave (60) while the last flying wave (59) is onscreen, often when it has finished killing off wave 59, the game ends right then, without launching wave 60.

I have attached a screenshot of the maze on level 59, but was not quick enough to capture the image of the game ending with still 75 seconds to go before wave 60.