Images breaking my page

[bodd54]

This is intermittent does'nt happen every time.
I have a 3 column block set to wide width with para's in blocks 1 and 3 and either a single image or gallery depending on this articles needs.
The images in the block are set as follows - single image:medium, Gallery:thumbnail.
When you visit the front page on many occasions the images placed in the middle are being displayed full size and not thumbnails, this then results in the centre block pushing the outer columns to show a single vertical line of unreadable text.
I have deactivated ALL plugins cleared the Cache and this behaviour still appears.
I have tried the support forums with no success and therefore must come to the conclusion this is a wordpress core issue

[bodd54]

Images of error and what it should look like

[bodd54]

error

[bodd54]

An update - after further examination, the google adsense code insertion seems to be conflicting with the image/gallery loading and causing this problem and seems to be restricted to desktop and my surface. As far as I can see tablet and mobile are working fine. For the desktop if you reload the page the error seems to disappear also