Version 1.9 breaks a local token.inc

[TomCrawshaw]

Hi, I'm running Civi 1.51.1 under Backdrop 1.22.1, and have written a local token.inc file which adds a few things, including an "addressee" token, which merges related contacts' names (so if the surnames match, it's John & Jane Smith, otherwise John Smith & Jane Brown). Under FuzionToken 1.8 I it was working fine, with the interpreted token stored - by default - in the civicrm_contact.addressee_display field. Upgrading to FT 1.9 breaks this, and although the token appears to be created correctly, it is not being written to the database, so (for example) SearchKit searches do not show it (the field is empty). I've not seen any error messages. Have reverted to FT 1.8 and it is working again as expected.

Any ideas please?