Unfortunately, up to now I haven't been aware of this ticket.

The repeated behavior happens only with Tablelist_tile, if the current theme is "aqua" and the first column is right-aligned.  Under these circumstances the procedure tablelist::seeCell, implemented in the file tablelistWidget.tcl, triggers an endless while loop.  To eliminate it, we have to take into account some internal details related to the way the header labels for the "aqua" theme are placed in their parent frame.

Here is the bug-fix: Locate the line starting with "set rX":

        set rX [expr {$lX + [winfo width $data(hdrTxtFrmLbl)$col] - 1}]

Just below this line insert the following code:

        if {[string compare [getCurrentTheme] "aqua"] == 0} {
            incr lX
            if {$col == 0} {
                incr lX
            }
        }

This patch will be contained in the next Tablelist release 6.4.