OK, blend is

MTE #205 95% (or more) - 2 weeks post roast
Eth Gambella Naturals <5% - roasted yesterday

The situation was that I was down to the last 50 or 60g of MTE, I had just roasted  the Gambella and found 3 or 4 beans that escaped the bag so I threw them into the grinder hopper on top of the MTE.

Prepared two shots yesterday and they were as expected: MTE with very light flavours of a roast at the end of its use-by date. I even made a capp for the second brew to provide some flavour.

This morning, there was about 25g of beans left. Made the shot and what did it taste of? Gambella! Not subtle but pronounced fruitiness. And this from at most 3 or 4 beans in 18 or 20g of beans.
Granted the MTE was flat but I wouldn't expect the Gambella to have that much influence. The only thing I can think of is that the flavours of the freshly roasted Gambella beans permeated the MTE beans as they degassed.

On the other hand this may be a common phenomenon that I had yet to encounter.

Any explanations or has any one experienced this before?

Thanks BW

I agree that the Gambella would dominate the MTE but we are only talking at most 3 or 4 beans worth in a 19g double (not 4 grams).

I could understand if it was a hint of Gambella, but this was like it was 90% Gambella I should also mention it was a latte in a 210 ml cup, not an espresso shot so it also cut through the milk.