Calc auto increment feature not working as expected

I have noticed that calc does not work as expected when I use the auto-increment function.

For example if I have too consecutive cells containing just numbers, e.g. 1, and I chose them then the 3rd in the row is also 1 as expected. Or if the step is bigger than 1 and I choose both also it works as expected, e.g. 1, 3 will produce a 3rd containing 5.

But when I have a mixed type like Face1, Face1 then the behaviour is different and it become Face2 regardless of how many cell I have chosen (1 or 2 I mean). I guess this is a bug if not something else. Any explanation or a way to change this behaviour?
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Do you mean that the third cell should also contain “Face1”? Try holding the Ctrl key while stretching the range

@JohnSUN, your comment is the answer.

No, @LeroyG, that’s not the answer. We must to write a lot to give a correct and comprehensive answer to this question (or to the question “Why is the selected text erased when I start typing?”, or to the question “Something appears in the active cell when I press Ctrl + V, but not always. Why?”). And they won’t always understand your answer. Therefore, it is easier to leave the question unanswered and spend time with people who really need help. (I just retell this)