Mobile top portion gets black when scrolling down a thread

[awesomewebsites]

When I scroll a BHW thread on mobile now, top screen goes black. I am sure it was not like this earlier

 

[OpenSauce]

Same thing happening on desktop safari

 

[BHWMPS]

Can you please let me know which OS you're both using? Also, steps to replicate it would be ideal so we can look into it - but send to [email protected].

Thanks.