In the Menu I created OR Header HTML OR Home Page Content.
Very weird issue. I can't recreate it, but after deleting all install files and reinstalling it made NO DIFFERENCE.
The error seemed to be stemming from page files or content.
So I deleted all the pages. Then Imported my own pages from my website using the new 2.2.3 advanced feature.
It seemed to resolve it, but it came back!!!
So I deleted all associated images and links to the home page, reset all the admin features related to the home page, recreated a new menu (deleted the old one) and uploaded new content.
BINGO BANGO.
We're back in business.
Worth investigating??? Maybe this can just be the resolution until more error's come in.
It's something to do with the IMAGE TAG and a media item.
Maybe the name / slug or PHP / MySQL...?
Who knows of course you'll know best but it's a seriously annoying bug.
Resolved...by deleting the Image from the content.
It's still in my Image Library. I'm going to delete permanently and re-upload. I think there's something going on in the MySQL / PHP something like repeated file name or something?!
Not sure if the client rectified this but the issue seems to have gone. May have been related the the import procedure but as all the pages are now completed with elements from the clients site there are no missing images or files.
So regardless this is closed with a big "?" as to why it occurred, to be concluded should the issue arise again.