Thank you for responding, I have a Canon Pro 100S. Colour profile is set to sRGB IEC61966-2.1 in Affinity apps. Fortunately the problem has vanished, I did update the Canon printer drive with the Majove version. At the time it didn't appear to help but instead of sleep I shut down the computer overnight and the problem vanished. It is a mystery to me.
Since I upgraded to OS Majove I have a printing problem which occurs in Photo, Designer and Publisher. Everything I print comes out brown, black and white text prints brown and white, colour graphics have a brown cast. Changing the IOC profile doesn't help. If I print from any application other than Affinity then the print is as it should be. Is this a Majove issue or an Affinity issue ?