The letters are part of a string that "moves" together. Try kerning left to right. If you need another type of absolute positioning, it might be best to create outlines and move letters individually.
For example, look at this text:
I like helping others.
If I remove the space between "like" and "helping", all the remaining letters and spaces to the right will move left. Same rules apply in kerning - just in smaller increments.
That all makes sense – but when I do it on my machine, the letters to the left also move to the right. Is that normal?
That does not sound normal. Does it happen if you start a fresh text block with no styles applied?
If you have any character or paragraph styles applied, try removing them one at a time to see if those might be the culprit.
This could also happen if you are using text justification.
Just tested it in a new document, new text block with no styles, and it doesn't happen there. Whew!
I didn't have any character styles applied to the text in the previous document, so unfortunately can't pin it to that – I did break the link to [Basic Paragraph], and they still move both directions. Really strange.
Oh geez – the text was centered. Changing it to left or right alignment fixes the problem, and it only moves in one direction.
Thank you for your help!