One great feature of PowerPoint is knowing that every text box is basically a mini Word document which means adjusting the cell padding can be done quickly and easily.
By default, all text is inset a small amount in each text box. Here is an example from the Microsoft PowerPoint 2016 default template. There is .1″ all the way around.
The cell padding, or inset, is easily customized. Select a text box, right-click and select Format Shape.
In the Formatting text pane, click the Text Options.
Click the text box icon.
Adjust the Left/Right/Top/Bottom margins exactly as needed.
Here is the same text box with a 0″ margin all the way around so the text is right next to the placeholder now.
And here is a callout bar with the text set to start 1″ in from the left edge.
Just some formatting ideas for your next presentation. Otherwise, you are stuck wondering why the text in a shape is not in the position it should be.