[traveller (Bo)]

Hi, need some help and advice from more experienced CCD imagers.
My QHY8 has developed a very strange artifact to the top right hand corner but only during the focusing frames using Maxim DL.
The attached frames are
Focus 1 sec using Maxim DL
Find DSO 10 sec using Maxim DL
Find star 1 sec using Maxim DL
Focusing 1 sec using Image Plus
As you can see, the artifact only appears on the first frame (focus 1 sec using Maxim DL).
There is no physical obstruction. I can't explain it.
Has anyone else experienced this?
This does not appear to affect the image captured (yet). Is this something to worry about? Time for a service?
Thanks
Bo