I thought this might be an issue with the voltage regulator but apparently that wasn't it.

I'm getting this intermittently, anyone seen anything like this before?

 

You got error codes waiting to be read. Get a bluetooth OBD2 reader, and get Torque (android) or whatever works on IOS.
Read the codes and let us know what they say.

 

I’d get the wheel speed sensors checked. Needs to be diagnosed with the proper tools.

 

Intermittent makes me think loose ground, have you checked the main engine ground just to make sure?

 

I asked my mechanic what they saw when they pulled the codes (forgot I had one of those bluetooth dongle things in the car anyway)

Here's what they said:
Tech said the fault was for DME, Aisin TCU OBD Relevant fault. Generic fault once scanned comes up as 000700. This relates to the TCU (Transmission module or engine module) not getting proper communications. Low voltages faulty TCM or Out of date system. Found battery voltages low, 11.3, partial Recharge the battery and retest, found battery weak, producing only 13.2 during idle, tech recharge battery to full, retest and found 13.9-14.2. Suggest battery change if a problem occurs. Also, if the issue persists, recommended to have the TCM / ECM checked, and updated if possible. If found internal TCM, ECM circuit is bad, replaced.

 

A weak battery can cause havoc in a Mini - performance issues, dying, etc. While not likely the cause, I would replace that asap.

 

yeah it's pretty fresh (6 months) but it's a AAA battery so I've got a warranty.

I found the ground point for the TCU but it's behind the dash so I'm going to inspect it with my fiber optic camera once I have a minute just to make sure it's not corroded / loose.

 

AAA came out and the battery and alternator checked out ok. Next guess is bad power/ground to the module since the car cranks strong