Safari CSS layout changed with new 5.1 version??

The latest release of Safari (5.1 6534.50) for OS X 10.6.8 and Windows that was released just after Lion was launched has caused some strange changes in the layouts of my Web sites. On certain pages with form fields, text on the same line has changed position to where some of the text now is positioned higher than other parts of the text.

The only difference in the text is the use of BOLD tags or SPAN tages around text. THis also seems to only occur in a row where there is text AND a form field, such as a text input field. Very very strange. No other release of Safari to-date has ever screwed up formatting - its typically IE that has all those problems.

Here is a sample of a place where some bold tags causes the text to jump around:

And the code:

<tr>

<td class="frmColTR1">Billing Contact (l,f)</td>

<td class="frmColL2">

<input type='text' name='bill_contact_lname' value="Last" size='18' maxlength='60'>

<input type='text' name='bill_contact_fname' value="First" size='18' maxlength='60'>

<b>Visa</b> expires on: <b>12/2013</b> in <b>29</b> months</td></tr>

I really dont want to have to go back and change hundreds of pages of our online application to have special code just for Safari to deal with this new formatting bug.

Does anyone at Apple have any ideas as to why this issue is occuring?