NVDA screen-reader skips pronunciation of outer 'div' when moving backward (using Shift+Tab)

Question

Here is my code snippet

div { border: 1px solid orange; margin: 10px; }

<div id="header" tabindex="0">Header</div>
<div id="slats-component" tabindex="0">
  <div id="totals-wrapper">Total [2]</div>
  <div id="slats-component-body">
    <div id="slat" tabindex="0">Slat1</div>
    <div id="slat" tabindex="0">Slat2</div>
  </div>
</div>

I am using only NVDA and only for FireFox.

Here is the actual behavior (what you do / focused element id / what NVDA reads):

• when moving forward (using Tab):
  1. Navigate to Header / header / Header
  2. Tab / slats-component / Total [2], Slat 1, Slat 2
  3. Tab / slat1 / Slat 1
  4. Tab / slat2 / Slat 2
• when moving backward (using Shift + Tab):
  1. Navigate to Slat 2 / slat2 / Slat 2
  2. Shift + Tab / slat1 / Slat 1
  3. Shift + Tab / slats-component / [nothing]
  4. Shift + Tab / header / Header

Actual behavior: while moving backward on step #3 NVDA reads nothing

Expected behavior: on the same step NVDA reads: Total [2], Slat 1, Slat 2

Pure CSS/HTML solution is preferable. In the meantime the html-snippet above is a part of AngularJS directive's template, so another solution is also possible.