Without seeing your config, it's impossible to say what you specifically did to make it do that

Howerver, if all of the time they are doing /cast [target={SLOT2}] Greater heal, I would suggest that either something is wrong with your selected Key Combinations, or FTL is enabled for the keys. Either of these could be resulting in a different macro being used than you are expecting to be used.

If you can't figure out the issue, you can copy your ISBoxer profile to clipboard through the right-click menu on "ISBoxer" at the top in the software, and then it can be sent in email, attached here as a file, or pasted on a site like pastebin.com. Then I (or anyone else) can paste it into ISBoxer (through the same right-click menu), and perhaps help you find the solution.