Welcome to the forum, fellow Meg IV owner here.
First off, is the car still under warranty? Either way, might be worth a visit to RenoTech in Hornsby to diagnose the issue, they are the best in the business. If they find the issue they normally write up a report which you can hand to your dealer.
Which dealers have you visited? Send me a pm if you prefer, as I can guide you a bit here with a touch of insider knowledge.
The tyre excuse is bulldust, ideally all corners should be the same, but as long as tyres match across each axle, you're fine.
The phase 1's do suffer from some electrical gremlins and I've seen reports of the same intermittent error on the RS280/300 FB Group. Fixes included new battery, power steering sensor, wiring loom etc... All electrical.