Consider the table below:

| Name  | Date of Birth    |
|-------+------------------|
| John  | <1978-11-14 Tue> |
| Peter | <1970-11-14 Sat> |
|-------+------------------|

Suppose we want to format time stamps differently, such as with the
following elisp commands:

(setq org-time-stamp-custom-formats (quote ("<%d %b %y>" . "<%m/%d/%y %a
%H:%M>")))
(org-toggle-time-stamp-overlays)

After realigning the table you get

| Name  | Date of Birth    |
|-------+------------------|
| John  | <14 Nov 1978> |
| Peter | <14 Nov 1970> |
|-------+------------------|

which is wrong because column widths are not uniform.  The reason, I
suppose, is that when computing column widths, org-mode ignores the fact
that the change of time stamps may have altered the length of the printed
string.

Best wishes,
Ruy Exel