Yes, iOS apps talk to each other. But Shortcuts doesn’t handle contact data in iOS unless someone specifically created a workflow doing so. And, if the shortcut is legit, you can view and control its data access.
So if the App Privacy Report says an obscured, unactionable workflow is suddenly accessing contact data—for some users only, on devices where it’s not installed, no shortcuts were created, and timestamps can’t be correlated to user actions—that’s the issue.
The report’s there so that, “if an app appears to be accessing your data in a way or at a time that you didn't expect, you can update your privacy settings or revoke permission.”
Shortcutsactions isn’t an app and this can’t be updated, so its inclusion is, at the very least, a bug. Without evidence to the contrary, it might also be malware.
Automation is inherently risky (Apple’s words, not mine), and they advise to, “review all shortcuts downloaded from the web or shared with you with extra caution to confirm that they function as you expect.”
Just last year, Shortcuts had a critical, zero-click exploit that allowed hackers to access sensitive data.
This also showed up without user interaction; of course people should try and validate that it’s not malicious. That’s not a conspiracy theory, it’s common sense.