Q&A images "Updates available" and "No updates" fail to load (floating bug)

Q&A images "Updates available" and "No updates" fail to load while browsing through the branches rarely.

Actual repeat mechanism was not found, so the bug seemed to be floating.

Easiest steps to reproduce:

1. Get into the branch where both of these images are available - read/unread Q&A topics exist (required condition);
2. Press F5 continuously until the bug occurs (from 3 to 15 times between reproductions).

AR: Images don't load sometimes (screens attached)
ER: All topic status images load correctly when the page fully loads.

Note:

1. Couldn't reproduce bug when only one image type is present on the page;
2. Hard refresh doesn't seem to make any impact;
3. Firefox is the only browser that gives such output (maybe this will give more clues about bug source):
   Case when images failed to load

   <img class="status-img-small" alt="Доступны обновления" data-original-title="Доступны обновления" src="/jcommune/topics/question/icon/unread.png">
   
       ::before
   
   </img>
   

   Html code when images load successfully

   <img class="status-img-small" alt="Доступны обновления" data-original-title="Доступны обновления" src="/jcommune/topics/question/icon/unread.png"></img>