Ah yes. But I think I've fixed that and have updated my Macro.
The interesting thing is that if the contents of the RTF are read directly to a variable (which is plain text) all those RTF codes are retained as text codes. But if it is first read to the Clipboard, the Clipboard has the different versions stored (including one without codes) and then using Keyboard Maestro's Remove Styles Filter seems to select the version that is just plain text without any codes. After that, a search for "some text" will find "some text". I got this by finding this post by @Tom