On last obj in mid of the map u get big black square dat blocks the view and it changes it shape and color when u move- probably somethign with the lighting
http://prntscr.com/7598ma - this one looks interesting 
Chapel last obj - black square bug
Same here since Fletcher update, black box, and it turns to be white light sometimes.
http://steamcommunity.com/sharedfiles/filedetails/?id=445643867
And there is one spot in Underground map where it happens too:
My system specs are as follow:
Windows 8.1
MSI R9 270X Gaming 2GB (Driver Packaging Version 14.501.1003-141120a-178000C, I updated to this latest version after seeing this bug for the first time, didn’t solve anything)
oh that black square turned into a white something … creepy
btw @DadoPeja last screen is funny … sometimes watching you 
have the same bug. looks the same as on all screenshots, so i decided not to upload mine.
I was worried I was alone since no one reacts in chat. It’s more annoying than you’d think at first glance.
Which video cards do you guys have and what drivers are you using?
Also have you tried to verify game data?
Had this issue some days ago.
It’s a corrupted texture of a decal shown as a black square (sometimes with a white circle inside).
For me it helped checking the game files with Steam.
After the verification the issue didn’t appear to me once more.
Note: its definately NOT a problem with your local hardware!
Regards.
Checking the game files with Steam worked for me too.
Thanks for the tip.
EDIT : well, it disappeared when using /switchlevel and exploring the map, but it’s still there during a real match… This or the file gets corrupted again in under 30 minutes…
Just tried again, it definitely doesn’t work and it’s just unplayable around it 
Seems to happen once the glass breaks as its normal till an explosion goes off near it.
I don’t know what was the actual technical cause but for me the game works totally fine since Steam’s file validation… even when the map (glass) gets bombed out.
same here:
http://forums.dirtybomb.nexon.net/discussion/10997/bug-at-chapel-or-how-the-map-is-called