I have the same problem !!! All of my images are the same W&H – see code :
<img class="alignleft size-full wp-image-472" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-405.png" alt="KAMA 405" width="380" height="220" /><img class="alignleft size-full wp-image-476" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-F2A.png" alt="KAMA F2A" width="380" height="220" /><img class="alignleft size-full wp-image-463" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-KARAT.png" alt="KAMA KARAT" width="380" height="220" /><img class="alignleft size-full wp-image-474" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-421.png" alt="KAMA 421" width="380" height="220" /><img class="alignleft size-full wp-image-477" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-F35.png" alt="KAMA F35" width="380" height="220" /><img class="alignleft size-full wp-image-462" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-FD14A.png" alt="KAMA FD14A" width="380" height="220" /><img class="alignleft size-full wp-image-475" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-422.png" alt="KAMA 422" width="380" height="220" /><img class="alignleft size-full wp-image-461" src="https://www.kama-pl.com/wp-content/uploads/2016/03/KAMA-F65.png" alt="KAMA F65" width="380" height="220" />
Not to mention, that it makes a “random” alignment (tested on Beaver Builder, built in WP editor, with different themes on)