Cell references in spreadsheet formulas with very long text strings do not always get updated correctly.
There are two simple workarounds to this problem:
1. Shorten the text string in the formula.
2. Put the long text string in another cell and use a reference to it in your formula
Example: If your formula currently reads as:
="Total this Quarter in US Sales - $"&SUM(A1..A10)
you could place "Total this Quarter in US Sales - $" into a cell (e.g. C20) and reference it in your formula:
=C20&SUM(A1..A10)