I did not see them first time round on the bridge, but now that I look closer I can see them. If I look on the left just above the 2 butments or pillars I can spot them and then follow them around. On the bridge the circles are much narrower and finer than in "the ruin", but I can see them now. I find them much more noticable on the ruin but even there I don't find them distracting except that I'm sure you are distracted trying to figure out the where they are coming from and why so many of us see them and you don't. My screen is not calibrated and yours is so I would tend to trust your screen more than mine and some of the others that might not be calibrated, however I have not noticed this on any except the last 2 of your shots.
Wish I could help but I really don't have any idea of the cause. In both shots though to me it looks like they radiate from a central point in the shot and seem to be wider and more prominent about 1/3 in from the edges, also more prominent on sides than top and bottom
Wendy