I have the exact same issue, verbatim as you. One file (in my case the primary character blueprint for my citybuilder) will not save, and when attempting to save will crash with the error “Illegal call to StaticConstructObject() while serializing object data!”
I took a backup of my project from several months ago & converted this old project from 4.22 to 4.23. Low & behold, in 4.23 the file that is causing the crash cannot save.
I’m convinced that this is a bug or issue being introduced by 4.23, as same as you my file causing the issue can save in versions saved back in 4.22. I only upgraded to 4.23 about 5 days ago, and encountered this crashing issue yesterday after attempting to modify & save the character blueprint for the first time since upgrading to 4.23.
I’m going to try to upgrade the project to 4.24 & see if that fixes the issue. My blueprint has a ton of code on it and I want to avoid building it all again by copying all the nodes & fixing the casts to a new blueprint as you had to do.
I too tried duplicating the file same as you with no luck. That duplicate will also crash when saved. It appears the issue is somehow linked intrinsically with whatever is in that file when used with engine version 4.23.
Like I mentioned, a two month old project from 4.22 and which worked when saving that file converted to 4.23 results in the engine crashing all of a sudden upon saving that file.