Is it only for this mission or all New Dark missions? We may need more details to figure out what the cause is in your case, but to start with you might check in cam_ext.cfg.
Code:
; ------------
; display mode
; ------------
; ensable Direct3D 9 based display system (instead of the legacy DirectX 6 one)
use_d3d_display
; use a single resolution for both menu system and in-game, with normal double buffering (in fullscreen)
single_display_mode 2
; same as above but with triple buffering
;single_display_mode 3
; alternative buffering mode that uses blitting instead of buffer flipping in fullscreen, the same method
; as windowed mode uses (vsync may sporadically miss frame starts on some systems)
;single_display_mode
; scale menu system to fit screen (in "single_display_mode") using 3D HW for best quality
; (if you're having trouble like a black screen when starting the game try mode 0 or 1)
; when "use_d3d_display" is enabled, 3D HW is always used, this only sets the scale mode to fit screen
ui_scale_mode 2