Electrical problem or ABS problem

Hello,

We are experiencing the following issue with a 2019 Skoda Octavia 3 (2.0 TDI 150, DSG-7).

In cold or damp weather, upon a cold start, all the dashboard warning lights come on and a "Brake Assist" error (code 03) appears. The car runs for 10–15 seconds; if we turn it off and start it again, the lights go out and there are no further issues.

The battery is new. We took the car to service, but they couldn't pinpoint the exact problem; they mentioned that the grounds and wiring need checking, although the wiring harness leading to the ABS module had already been replaced some time ago. They suspect the issue lies with the ABS module itself but aren't certain. Has anyone encountered a similar problem, and what do you think it could be? This issue has persisted for three years; the error and dashboard lights don't appear every time we start the car. In warm weather, there are no issues or error messages.

Also, do you know if the ABS module can be refurbished?