Windows 7 - Losing Argument Context, Windows 10 is fine

Greetings ~

I am trying to track down a problem running whereby running a simple script on Windows 10 is successful, but running the same script on Windows 7 fails. The script is very simple, it invokes an external script which opens a browser to a URL saving that UiBrowser object as an “Out” argument. This Browser object is then passed into another external script (as an In argument) which performs some navigation and fills out two fields.

In between the two calls, I have a Log Message (just for testing this issue).

The Browser variable that is used in the main workflow comes back from the first external script as NULL in Windows 7 (generating an “Object reference not set to an instance of an objecct” error if you try to log it). Yet this script runs flawlessly on Windows 10. The IE version is the same on both (11.0.43).

What am I missing?