kryptik.ak threat detected on one website

Plan A:
You can try to contact the Kanvaso.com team again and inform them about disadvantages of this obfuscation. If they are interested they are welcomed to join the discussion as well.
Plan B:
The exclusion configured in the picture allows you to download the obfuscated script:

The web browsers often save a copy of downloaded files on the disk in browser cache (or Temporary Internet Files). The exclusion of the folder could be needed too. Example of the exclusion:
C:\Users\your_user_name\AppData\Local\Microsoft\Windows\Temporary Internet Files\*