Beko, WMA 641 W sometimes doesn't wash properly ?

Please help!

We've had our Beko WMA 641 W for well over a year and we've notices that on one particular wash program the washing smells, (a bit like curry), but washes OK on a different programme.

This wouldn't be so much of a problem, but the problem programme is the one we want to use most of the time.

It is the "Cottons 40" programme which is a 6Kg wash. We have tried cleaning the washing machine fully, emptying the filter, using different detergents and we don't eat curry! I suspect the problem is related to the 6Kg wash size not cleaning fully.

Has anyone else heard of a similar problem, or know how I can get the program to work.

Thanks
Your humble servant.