Truxton II scrolling speed up glitch

[Furry Fox Jet Pilot]

So I was playing Truxton II in MAME last night, and when I got to the section just before the last boss, I held down the C button to make the scrolling speed increase, and I found that if you do that, the last boss won't spawn, and instead you keep going into a screen of empty black and then it loops back to Stage 1, but no enemies spawn. Instead it shows several layers of sprite tile corruption until you reach Stage 4's boss. Has this ever happened to anyone else?

[trap15]

Not surprising, the speed up button isn't actually meant to be used. You shouldn't have it mapped lol

[Despatche]

please don't use the debug button in vimana and tatsujinou, not even for fun

[Furry Fox Jet Pilot]

Not surprising, the speed up button isn't actually meant to be used. You shouldn't have it mapped lol

I honestly thought it was a legit part of gameplay, although now I realize that speeding up and making swarms of enemies spawn at once does not work so good in your favor.