Welcome to the UiPath Community @kwspaargaren
Yes I think the code is developed originally in the legacy windows .net 4.6 framework.
This is correct and will be like that only.
Legacy windows process will not be completely compatible on newer windows .net5 framework
You can mention more details if the issue is something more than this.
Below link explains the way UiPath handles the framework change in windows.
Automation Project - Framework
This post explains that difference nicely
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