Hi,
I have been an affinity user for a number of years, I have Publisher, Photo, Designer.
I am seeing really unpredictable behaviour with the latest versions of these tools. Tonight I wanted to use the clone brush. I pasted in an image. I made sure it was rasterised. I then held the Alt key and left clicked. The cross hairs briefly turned to a circle. I then tried to paint (as I have done a 100 times before) The History register "Clone Brush Tool", but a message appeared. "You must Alt Click to set a source before trying to clone". I tried numerous times. I made sure nothing was selected. I duplicated the layer and tried on the duplicated layer. Nothing worked.
I selected the image and copied it into a new affinity photo file. Same behaviour. No clone.
I closed down the program, opened it up again. This time everything worked. I have been hitting this issue repeatedly since the most recent update. A feature just stops working for a period of time, then by creating a new file or restarting the program it works again.