do javascript in Safari Applescript does not returns arrays any more

Hello,

I have recently updated to OSX 10.12.4 (Safari 10.1 / Applescript 2.5) and running old scripts that rely on arrays to be return from Javascript with a do javascript command inside a Safari-Applescript stopped working

eg.

when I enter

tell application "Safari"

     tell document 1

          do JavaScript "'1,2,3'"

     end tell

end tell

I get a String in return, same works for numbers

but Arrays only return an empty string... seems to be a bug, since

tell application "Safari"

     tell document 1

          do JavaScript "[1,2,3]"

     end tell

end tell

used to return a native AppleScript Array -> {1,2,3}

Does someone has this bug as well with these software-versions and if so, were I can tell Apple to fix that?