I have this overlay scene The numbers are all part of the same text with spaces among them. If I don't make them into meshes and run the game, some spaces between them get lost so the numbers are not where they supposed to be(every number in the start of the respective box). If I alt+C and make them into meshes it works. Why does it fail to work if they are part of text?
Text objects are converted to a mesh with a plane for each letter. The planes get a rendered texture of the chosen font.
Unfortunately this render does not 100% match the text object it is based on. That is the reason for the size and location differences.
I suggest to split your text object that you get one for each button. This reduces the visible location and size differences. Additionally it allows you to parent the text to the button.