we are about to do the final transition from K2 to K3 (3.3.0) with our project. I just converted all content files with the upgrade script at https://getkirby.com/docs/cookbook/setup/migrate-site#folder-and-file-structure. Most of the content seems to work fine.
However, we use structure fields as participants lists. When I try to open the migrated participants lists in the panel, instead of the structure field it shows a red error box with the message “Cannot read property ‘length’ of undefined”.
This occurs with most of the participants lists but not all (maybe not the more recent ones or the ones with just one or two entries?).
This is what I get in the console:
Can this be related to some broken formatting or invalid characters in the content TXT file? Any hints what to look for? (As I cannot share the original files with names and addresses)