Artifacts in Panorama Stitches

[Wanderer3]

Recently I have begun to get strange artifacts when my panorama stitches are completed.  These do not show up until after the image is finished and exported.  They are small (about 1/4- 3/8 inch long) narrow white bands scattered about the image randomly, somwhere around six in each image, and are simple, straight, very narrow, uniform in size, shape and color, and about the width of pencil lead.

I do a lot of mountain range photography and use HDR on most images because the scenes are usually high contrast.  In this case I do HDR merges ( 5-6 files each) on two or three images, then do panorama stitiching on the two or three of these HDR merges so that most of the visible mountain range is included in the finished photo.  I've done this for quite some time and never had artifacts in the images until the past week.  I can remove the artifacts with inpainting but it seems they sometimes reappear, although I am not certain of that as I may have missed those the first time I looked.  

I updated my Affinity Photo as soon as the update was issued and I am wondering if that might have something to do with is as I never saw such artifacts before updating.  I did a search here for this and also searched in the Workbook but found no mention of anything like this.  Any help and advice would be appreciated.  The files are much too large to attach and I don't have the time right now but if the description above isn't adequate I can resize and send them later.  But they are really simple - just very small white bands.  Thanks in advance.

[carl123]

See this thread... you can also try the latest beta to see if the issue has been cured in that.

 

[Wanderer3]

The artifacts in the first post look exactly like the ones I'm getting.  However, I did two panorama stitches yesterday eveing that didn't have them.  Hopefiully they won't return but if they do I will apply the solution done by the second poster.

Thanks for the helpful info.