Spacing irregularity probably css clash

Here is the HTML of the 3 paragraphs:

<p class="lead"><strong>1st item with spacing as expected</strong><br> This is the first line<br> This is a second line<br> Third line</p>
<p><strong>2nd item which seems to be spaced out</strong><br> This is the first line<br> This is a second line<br> Except for the third line which is spaced as expected</p>

<p><strong>3rd item</strong><br> This is the first line<br> This is a second line<br> Third line</p>

<p>All three paragraphs above have been set up identically. I can’t see why subsequent paras have all lines spaced out except for the last one. This para shows how normal text is spaced. All the three blocks above are separate paras but the individual lines are just breaks.</p>

If you look at the CSS for the ‘lead’ class, you will find this:

.lead {
    ...
    font-size: 21px;
    font-weight: 200;
    line-height: 30px;
}
.lead {
    font-family: 'ArsenalRegular';
    font-size: 14px !important;
    line-height: 20px !important;
    color: #61726C !important;
    font-weight: normal !important;
}