Table alignment issues InDesign CS4

Hi,

Can anybody help me on the following issues in InDesign CS4.

We have an table which has 50 rows and 23 columns. All the cell contents is in the number format (example: 56.90) and are aligned on decimal point (dot alignment).

Also, the table content has XML tags.

When we export the table as PDF, we have the issues that the table column texts are not aligned (dot aligned) properly in the exported PDF file.

We used the default "High Quality Print" InDesign PDF preset settings but without "Create Tagged PDF" option enabled to export the PDF. In this PDF, the columns texts are not aligned (dot align) properly. It look likes zig zag. (Please see the below image which is not aligned properly)

But when we enabled the "Create Tagged PDF" option in the preset, then there is no issues in the column text alignment.

Is this bug in InDesign CS4 application. Please suggest.

Thanks,

Gopal