MVS Metal Sug image duplication issue...

[Asayuki]

Two different board sets or monitors with exactly the same issue is not impossible, but very unlikely.
If it's a defect in the programming of the game, then emulators might show the same issue. Try MAME on a screen where the refresh rate is forced to 60Hz. (EDIT: actually at the same refresh rate as the real hardware, with -vsync option enabled)
Yet every human being is one of a kind. There are people who can hear the 15kHz whining of LOPTs in CRT monitors while normal people can't. There are people who can thrash a fire button faster than a danmaku shooter can register while normal people can't (I remember a thread about this here on AO). There are also people who see CRT screens flicker when using refresh rates less than 75Hz. I don't see any reason why you couldn't be able to see a screen refresh delay while others can't.

[Wurstkopp]

This might just be a matter of age? My sister, who is almost 20 years younger than me, is always complaining bout "these old **** flickering monitors". She grew up in a world beyond 50/60 Hz refresh rates and isn't used to it.

[GIF]

Age ? Probably not, I'm 35 years old and grew up with CRT TVs

[Wurstkopp]

Then you just have super powers.

[Wurstkopp]

Come to think of it , when I'm smoking pot I have these powers too.

[leonardoliveira]

Each person has their own brain wired differently internally. It's "known" that some people have "a better brain" for processing visual input.
And some people are barely able to tell apart a PC game or movie running 60FPs from 120FPs.

When I was younger I could hear the whistle noise from the flyback transformer when people turned on any CRT TV on the house. Now that I'm on my 40s I know I can't (we still have two CRT sets here which eventually get used for classic gaming and they were around here at the time when I could hear that).

So let's give the OP the benefit of the doubt, maybe.

After reading the whole thread again, to me it seems obvious the way the sprites are doubling have to do with the way the game update objects on the screen (programming). When the CPU gets too busy video list updating gets slowed down and the objects stay on the screen longer than they should generating the effect the OP described.