The "Park operation cancelled" Warning message triggered by N.I.N.A. when parking the mount from inside this software has been fixed with the release of a BETA version of the Avalon ASCOM driver that is available with the temporary link below:
https://drive.google.com/file/d/1ZiKylYMS29ch6jjiRGY7NTRjYPfVzDxX/view?usp=sharing
More information on this topic thread.