How to center a multiline text in label?

[Boyang_Wang]

Hello,

I am trying to create a symbol style with two lines, one line from one data field. I used Python script [field1]+"\r\n"+[field2] to create multiline labels, but I don't know how to control the alignment. As you can see in below screenshot, some letter B are aligned to the left and some are aligned to the right.

I tried to change label symbol position setting, but the alignment setting was greyed out. I am using Maplex Label Engine. Is there any way to adjust this?

[RhettZufelt]

I see the same thing unless I select "centered on point".

R_

[JesseWickizer]

When labeling with the Maplex label engine, horizontal alignment is set by the label engine. Use the Maplex Stacking controls to constrain the alignment to center.