Have you emailed the Magix company about it?
When I had problems with their product, the email support wasn't all that helpful, but it's worth a try.
Maybe it's the computer, have you tried recording in other programs to test it?
I'd recommend checking the computer usage as well, something else may be interferring and throwing off Magix.
Also, maybe try uninstalling then reinstalling the program to see if that helps.
If there's still a problem, then I'm not sure. Emailing Magix is probably the best option.

have you tried to change asio settings?(preferences)