Refreshing a page will change it - html

Question

How can it be possible that the simple refresh of a page will change how the content it's displayed, while the content itself it's not changed?
Specifically i have some divs with inline-block style that are supposed to stay in line on desktop page and to fall below each other on smaller screen.
The first time i load the url, writing it in the address bar, i see correctly the divs in a straight line. But if i hit F5 and refresh the last div falls down like the simple act of refreshing put some misterious space among them. Since the first load of the page to the refresh nothing is changed, not a single line, not a single content nor the screen resolution obviously.
This is not happening just sometimes, but regularly on the same page.
I could link the whole page but it's on a production ecommerce site and i don't want to advertize it. I'm reporting here the extract of the code, but i'm not sure it's enough to fully address the problem, but maybe someone has a clue that will point me in the right direction.
<div style="border-top: 1px solid lightgrey; border-bottom: 1px solid lightgray; padding: 5px 0;margin: 5px 0;">
<div style="display:inline-block;min-width:114px;line-height: 17px;vertical-align:top;" class="emboss">
<a href="https://shop.suonostore.com/spedizioni-e-tempistiche" style="line-height:20px; color:#47a447; font-size:11px;" target="_blank" title="Vedi maggiori informazioni sulla disponibilità">
<img class="aligncenter" style="float: left; margin: 1px;" src="/wp-content/uploads/stock3.png" alt="Alta disponibilità" title="Alta disponibilità" width="31" height="auto" border="0"><strong>DISPONIBILE</strong><br>IN SEDE<br><em> Stock Alto</em>
</a>
</div>
<div id="div_consegna" style="display:inline-block;min-width:258px;vertical-align:top;margin-left:6px; padding: 5px 0px 0px 0px;">
<table border="0" style="display:inline-block;">
<tbody><tr>
<td align="left" style="padding-left:0px;">
<span style="font-weight:bold; color:#333; font-size:12px; color:#000000;">Ordina entro</span> 
</td>
<td align="right" style="line-height: 25px;padding-right: 3px;">
<span style="font-weight:bold; color:#333; font-size:12px; color:#000000;"><strong> <span id="tc_th">18H</span><img class="centre" style="float: centre; margin: 1px;" src="/wp-content/uploads/due_punti.gif" alt=":" width="5" height="auto" border="0"><span id="tc_tm">37m</span></strong></span>
</td>
</tr>
<tr>
<td colspan="2" align="right" style="line-height: 12px;padding-right: 3px;">
<img style="float: left; margin: 2px; padding-left: 4px;" src="/wp-content/uploads/espressa.png" alt="consegna_espressa" title="Spedizione Espressa entro le 16:00" width="35" height="auto" border="0"><span style="font-weight:bold; color:#333; font-size:12px; color:#000000;">
ti arriva il giorno</span>
</td>
</tr>
</tbody></table>
<table border="0" bgcolor="#000000" background="/wp-content/uploads/Calendario.png" alt="agenda" title="Data di consegna" width="110" height="55" style="display:inline-block;">
<tbody><tr>
<td rowspan="2" style="font-size:32px; color:#000000; padding-bottom: 3px; padding-left: 2px;">
<strong>27</strong>
</td>
<td align="center" style="Font-size: 9px; min-width: 46px; color: #000080; padding: 5px 1px 4px 2px;">
Lunedì
</td>
<td style="line-height: 25px;Font-size: 8px;font-family: Helvetica Neue Light;padding: 8px 1px 0px 3px;color:#8b0000;" align="right">
2020
</td>
</tr>
<tr>
<td align="center" style="padding: 0px 0px 4px 2px;color:#8b0000;font-size: 12px; min-width: 66px;" colspan="2">
<strong>Gennaio</strong>
</td>
</tr>
</tbody></table>
</div>
<div style="display:inline-block;min-width:255px;vertical-align:top; padding: 5px 0px 0px 19px;">
<form class="cart" method="post" enctype="multipart/form-data">
<div class="quantity">
<input type="number" step="1" min="0" max="" name="quantity" value="1" title="Qtà" class="input-text qty text" size="4" pattern="" inputmode="">
</div>
<input type="hidden" name="add-to-cart" value="54325">
<button type="submit" class="single_add_to_cart_button button alt">Acquista</button>
</form>
</div>
</div>