Problem solved after updating to STP release 232.

The symptom has returned. 🙄 Presumably something in my installation is affecting AppleScript's recognition of whether Safari Technology Preview (STP) is running. I'm looking into replacing STP with Safari until the above symptom resolves (again!). Where in the user account is STP's last session and/or saved application state information stored? I've found lastsession.plist, but its date stamp is from December 2021 rather than November 2025. I've also found the Saved Application State folder in the user Library folder' STP folder. However, it is empty. The export browser data dialog in STP does not include last session or saved application state data (i.e., open windows and tabs). Thanks in advance.