Unintended actions during keyword test run

This is an interesting problem for sure.  You may indeed be able to sort it out by looking at the object properties or the specifics of the line in the Keyword test that is executing the click.

However, another avenue is to take a different approach.  Often in TestComplete the same thing can be accomplished by more than one method.  In this case I would suggest trying the Keys method to accomplish selecting the tab you want.

The first step is to see if your application supports keyboard access to the tab.  With focus on you application press your Alt key.  If the application supports keyboard accelerators for the tabs you should see them displayed something like below.

Here you can see "H" selects the Home tab, "I" selects Insert and "T" selects Tools.

If you see them then this approach will likely work.  In your keyword test you'll want to select the "Call Object Method" entry in the Test Actions list.  Then select the main application window as the object.  From the list of methods choose "Keys"

For the value enter "~" followed by whatever keys(s) your application showed for that tab.

Click "Finish" and run it.  Hopefully it works.