VISA Foreign Currency Rate is Consistently Better than the Rate given by Mastercard

In the past the Mastercard currency conversion rate was generally better than that of VISA. However I am beginning to wonder if that is still the case.

I have Halifax Clarity (Mastercard) and Nationwide Select (Visa) credit cards. Both cards have no foreign currency charges. I have done a number of transaction at the end of December/early January using both cards on the same dates. On each occasion Visa gave me a better exchange rate (between 0.2% - 1% better).

Also comparing the Mastercard rate ( https://www.mastercard.co.uk/en-gb/consumers/get-support/convert-currency.html ) and Visa rate ( https://www.visaeurope.com/making-payments/exchange-rates ) using their websites gives a similar result.

Has anyone else noticed this?