Hi @benbodhi ,
For a manual fix see end of this post.
If i deactivate the plugin “SVG Support”, no more errors, post can be saved.
Could be something incompatible with php version 7.4.x -> 8.x.
Did the following tests:
- In testing i deactivated all plugins except “Advanced Cusstom Fields – 6.3.6”, “Custom Post Type UI – 1.17.1” and “SVG Support – 2.5.8”, WP core is 6.5.5, PHP Version 8.1.x. problem still present.
- I tested with older versions of SVG Support back to 2.4.x, same problem
- Downgrade of WP Core to 6.4.x and 6.3.x, same problem (but staying with php 8.1.x)
We were running fine with 2.5.5 for some time combined with wp core 6.3.x and php 7.4.x, then did some upgrades, including WP Core and PHP to 8.1.x and noticed the errors.
I also found that creating a completely new post the error is not raised, post can be saved and changed.
Manual fix for the problem, example postid == 123:
I noticed multiple DB entries in wp_postmeta for postid=123 with meta_key=inline_featured_image, meta_value=null but there should only exist one entry for this meta_key for each unique post.
After removing these entries from the db the post can be saved again.
How and when these multiple entries were created i can not reproduce at the moment.
Hope this helps.