Cross/Analog keys toggled with LShift/LAlt combination

[LunaMoo]

Here - you can find explanation of the issue.

And for example here you can test your keyboard against it.

Basically it's your keyboard problem, most keyboards on the market are affected by this althrough different combinations are affected on different keyboards(hence the test demo I linked above). It's design limitation and you can't really "fix" it other than remapping your keys to a different ones that work with each other.

That's also why people on most emulation forums keep telling people who has only keyboard to buy and use a controller designed for games, like a gamepad, since even cheap gamepad is free of such issues.