Hi @MR___
Thanks for the question. The answer to which is most likely that WP is unable to save the value.
The reason for this is due to the string length of the meta_name which you are trying to save. The more depth (from repeaters / flexible content fields), the longer the value name saved in the DB.
Some database tables contain character limits on the metaname column. This changes from the postmeta, to the options and the usermeta tables.
Another possibility is that your server is running out of variables or memory during the save and is simply failing to execute the save function.
Best bet is to loog in your server logs. They will hopefully show the error that is occurring.
Thanks
E
