Display issue after last update

Hello,

I’ve been using your great plugin since years on my art gallery site and unfortunately it seems I’m having a display issue since the last plugin update (1.12.7).

I have currently 6 gallery pages (with 12 images in each gallery), 3 columns with 250px fix image width and 5px distance set between the images. Content area is set to 760px wide, 0 padding and 0 margin. It has been working flawlessly until the last update, when the display changed to 2 columns, although I haven’t change anything either in the plugin settings or anywhere else on the site.
The same problem occurs with my widget gallery on the right sidebar: it used to be displayed in 4 columns with 45px fix image width and 1px distance in a 183px wide content area on each page, now it’s only 3 columns.

If I change the distance of the columns on the page galleries to 4px (3×250 + 2×4 px =758px) it’s 3 columns again, and respectively if I change the widget gallery settings to 0px image distance it’s 4 columns again, so I assume there is some coding issue with the padding of the galleries in the last update, but I can’t figure out what (Chrome Inspect shows the right values, no extra padding visible anywhere).

I would really appreciate if you could look into it and figure out what’s wrong.

For now, I only changed the settings for one gallery on this page:
https://www.12images.net/galleries/sailing-seven-seas/

this is one gallery page with the original settings:
https://www.12images.net/galleries/skyscapes-and-horizons/

and this is one random image page with the original widget gallery settings:
https://www.12images.net/galleries/sailing-seven-seas/homecoming/

Thank you very much for your help in advance.

The page I need help with: [log in to see the link]