Would it count as a "political reason" if their risk management calculations crossed a threshold where it's worth it to move the gold back? I imagine such calculations are done and revised all the time and account for the perceived stability and reliability of a country.

Russia's frozen assets probably were considered safe by the similar calculations. Everything is safe until it is not.

I don't understand what point you are making.

The gas supply from Russia was announced as secure* until it was not.

* mainly by Russia and people on their payroll that is.