I do use the "edit" and "edit passes" buttons when I change the parameters, but how would that change the tool? Doesn't Aspire recognize a tool by the number, regardless of the parameters you set for a certain toolpath?
It is entirely possible that it's some form of operator error, but I can't figure out what it could be. When this happens, I usually open up the toolpath to see which tool I have selected, but it's still the same. I have picked the wrong tool several times when creating new toolpaths (usually because the previously used tool is pre-selected), but this always shows when I run the preview. I can't recall having this problem in a new toolpath though, it appears to happen when I edit them.