I understand how frustrating it could be when your typing flow gets disrupted due to these random double spaces. Let's try a few things to get to the bottom of this.
Since you're experiencing this on multiple devices and keyboards, this makes me think the issue might not be hardware-related but possibly linked to the settings or software. If you're using a particular text editing software or a specific app while this happens, it might be related to the settings or even a bug within that app.
First, I would suggest checking your settings in System Preferences -> Keyboard. There's an option called "Add full stop with double-space." While this isn't exactly what you're experiencing, it's worth disabling it to see if that helps.
Next, let's rule out any potential software or app-specific issue. Try typing in different applications and see if you experience the same problem. If it's specific to one app, it's probably related to the settings or a bug in that application.
Lastly, have you been using any text expansion software or do you have any shortcuts set up in your Keyboard settings? These could potentially interfere with your typing and produce unexpected results. Check your System Preferences -> Keyboard -> Text for any shortcuts that might be causing this.
I hope these suggestions will help you get closer to resolving the issue. Let me know how it goes!
Reference:
1. Apple Support: Change the keyboard settings on your Mac
2. Apple Support: Use autocorrection