UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:51.0) Gecko/20100101 Firefox/51.0

Steps to reproduce the problem:
With the following css used to line-clamp I have found that although it respects the line-height to display the text the last line clamps the text too short resulting in a different height when clamping is active.

By active clamping i mean text that overflows the number of lines specified by -webkit-line-clamp.

ie. 3 lines of text that does not overflow would equal 72px high. 3 * 24px line-height.

but when text overflows and clamping is active (ellipsis appears) the height of the div shrinks to 67px high.

    line-height: 24px;
    font-size: 13px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    overflow: hidden;
    -webkit-box-orient: vertical;

What is the expected behavior?
The height should be 72px high (3 * 24px) but instead the last line gets cut too short and the height is 67px high.

What went wrong?
I believe that when line-clamp is active that it reverts to the browser default line-height when clamping the last line.

This can be tested by setting line-height: initial; the problem does not appear and a height of 45px appears for 3 lines of text overflowing or not. Using the default browser line-height of 15px for 13px font-size.

Did this work before? No 

Does this work in other browsers? N/A

Chrome version:  56.0.2924.87 (64-bit)  Channel: stable
OS Version: OS X 10.12
Flash Version: Shockwave Flash 21.0 r0