Solved Child theme throwing warnings on one site (not others)

When I activate my child theme on site https://famvin.org/en/ I get a debug log filled with the following warning:
12-Sep-2026 16:57:43 UTC] PHP Notice: WP_Theme_JSON_Resolver::get_user_data(): Error when decoding a theme.json schema for user data. Syntax error in /usr/www/users/XXX/famvin-org/wp-includes/functions.php on line 6260
This theme is active on 6 other sites in the same multisite network and never generates this error.

I googled and Google AI tells me that there is a corrupt theme.json file causing the error. But, the child theme has no theme.json. If I run with Divi 5.12.1 (no child) on this site, there are no errors. But, I need a particular action that is coded in my functions file, so I need the child theme.

Thoughts? I have tested every *.json file I can find in my site. ET says it is not Divi itself, and I tend to believe them. I am thinking that there is something corrupt[ed] in an option or in the particular site, but I can not seem to find it.

 

I finally resolved the issue: I copied the theme to a new directory and renamed it (new directory name, new name in style.css). Switched to the "new" child theme and all is well. My only guess is that there is something corrupt in the database associated with the "old" child theme or something cached that is corrupt. There was never any theme.json anywhere in the child theme.