iPhone hack Shortcut suggestion

I would say not a hack. There are 2 ways to receive a shortcut suggestion. The first is by an app, in which it will specifically ask you if you would like to add a shortcut. This could be a coffee app that creates a shortcut for you to order a coffee and can even be activated by a Siri phrase. The second is by Siri and will suggest a shortcut by actions you do and by information it receives from other apps. A coffee app can notify the system that you order a coffee at a certain time. If Siri notices that you order that coffee at a certain time or on certain days, it will offer up that suggestion on its own. Siri also gets data from messages, so if it detects a day and time in a message, it may suggest a reminder.

Siri does make mistakes and may have misinterpreted a series of numbers from a message as a reason to suggest a shortcut suggestion to call the number. You can make the suggestion more accurate by holding your finger on the suggestion and tapping suggest more or less.

You can also shut off suggestions from a specific app or all suggestions. To shut off for a specific app, go to Settings > app name > Siri & Search. There are 3 settings under Suggestions that you can shut off. To shut off all suggestions, go to Settings > Siri & Search. There are 4 settings under Suggestions from Apple that you can shut off.

No, it's unlikely a "hack." You'd have to know where the suggestion came from. But, simply dialing a number isn't going to do anything.