Confusing output of `check`

I ran this command
rclone check gd1:'Google Photos'/2017/07 gd2:'Google Photos'/2017/07

And I got a bunch of lines like this:

ERROR : 20170706_114303.jpg: File not in Google drive root 'Google Photos/2017/07'
ERROR : 20170710_181544.jpg: File not in Google drive root 'Google Photos/2017/07'

So which remote is missing the files? gd1: or gd2: ? Does ‘root’ mean the first remote?

Have you tried with slash at the end of both paths?

rclone check gd1:'Google Photos'/2017/07/ gd2:'Google Photos'/2017/07/

Yes, just now; result is identical.