Issues with printing my designs on paper before sublimation

Hi everyone,

I did post about this once before but the problem is still here , so I'm wondering if anyone has any advice!

I have a range of designs which I sublimate onto mugs, coasters etc. They are all the exact same background with another image placed on the background. These images are all different. I design these in Canva.

I use an Epson L805 sublimation printer, and when I print a design on it, sometimes the background will appear very faded. This can suddenly happen with images that have been printing correctly for over a year, and can be one in a line of images I print on any given day, or more than one, or none of them! Sometimes a background prints as a slightly different colour, so say the normal print on the mug would be green, the slightly different one will be more golden. The faded one will just barely show.

All my settings are the same for each print. I don't change anything in my printer settings as usually it works perfectly. But why do I get these random errors? Most of these designs have printed perfectly in the past then seemingly randomly go wrong!

I know this sounds really odd, but please help if you can - or even if you've had this happen, let me know, so I know I'm not going mad! I'll answer any questions if I can but please be aware I'm not techy, so you might need to explain like I'm 5... :D