I did send an email, but just in case, I’ll post here too.
The game stutters every 10 seconds precisely, no matter where I am or what I’m doing, even in the main menu. After a while troubleshooting, I finally discovered that when I turn off my internet and play the game, the stuttering is gone. This leaves me to believe the issue is something to do with an online service, perhaps fetching Steam friends activity status might be the culprit considering I have hundreds on my friends list and I’ve heard of games before having an issue when you have hundreds in your friends list. I don’t want to play the game offline, because I like to have my Steam hours tracked. And playing online means a guaranteed stutter every 10 seconds. Neither is ideal 
I saw that someone else had the same problem on the Steam forums so I shared my theory that it was to do with a large friends list. They cleared out their friends list from 300 down to 30 friends and that fixed the problem for them. This means the cause of the issue is certain: having a large friends list results in frequent stutter. I hope the issue can be fixed more swiftly now that the cause is known for certain.
(Steam) Adding to this. Having the exact same issue ~200 friends list and stuttering every 10 seconds. Offline mode with no friends fixes stutter. Prefer to play online, though.
Thank you for reporting, I saw your mail about this too. Are you playing on Steam?
I’ve reported this to the rest of the team.
Thank you for your response.
Yes this is on Steam. My friends list is ~390.
While you’re here, I’d like to report some more bugs in case you’re not aware of them. These following instincts are bugged:
• Bounce on Trampoline 10 times in a row
• Drive Toy Car at High Speed for 20 seconds
• Tag the Founding Father’s Face