Make sure none of the compatibility flags are set on the Opus binaries.
Try setting Preferences / Miscellaneous / Advanced: dlldir_security to FALSE and rebooting. It can affect launched apps by influencing where they look for implicitly loaded DLLs. (But if it does not change things, set it back, as it is more secure in the default TRUE state.)
Try setting Preferences / Miscellaneous / Advanced: def_func_cd_sourcedir to TRUE. It can affect launched apps similar to the above setting and also affect where they load their config files, if they assume the CD will always be their own folder. (But if it doesn't help, set it back to the default of FALSE, as it is more secure.)
Aside from that, I do not know any way that the launching program could affect the DPI scaling or similar of applications which it launches. You may be looking at an operating system bug (there are a lot of OS bugs still in Windows 10 if you are mixing multiple monitor DPIs at the same time, or without rebooting after changing, for example) or a bug caused by 3rd party software that is interacting with Opus and the apps being launched.