Firstly, thank you CharlesVBD 59, but the settings for the conf.ini items you've listed are already the same in my installation.
Here's a chunk of the logfile from my latest attempt at the He 177 QMB test mission, beginning approximately with the warning mentioned by vpmedia:
MaxAnisotropic (1.0 = none) : 16.000000
WARNING: 'Perfect' Mode required pixels shaders
WARNING: 'Perfect' Mode is not supported for this combination of hardware and drivers.
15 Splashscreens available.
BAT Version Info (from BAT.version file): IL-2 1946 · Battlefield-Airborne-Tactical · v3.3 · PATHFINDER
INTERNAL ERROR: Str2FloatClamp() - Clamped 3 -> 2 (delta = -1) to Range 0..2
INTERNAL ERROR: Str2FloatClamp() - Clamped 5 -> 2 (delta = -3) to Range 0..2
INTERNAL ERROR: Str2FloatClamp() - Clamped 3 -> 2 (delta = -1) to Range 0..2
INTERNAL ERROR: Str2FloatClamp() - Clamped 75 -> 32 (delta = -43) to Range 0..32
INTERNAL ERROR: Str2FloatClamp() - Clamped 120 -> 60 (delta = -60) to Range 0..60
INTERNAL ERROR: Str2FloatClamp() - Clamped 600 -> 32 (delta = -568) to Range 0..32
INTERNAL ERROR: Can't open file '3DO/Effects/TEXTURES/JetSmoke.mat'
WARNING: object '3DO/Effects/TEXTURES/JetSmoke.mat' of class 'TMaterial' not loaded
INTERNAL ERROR: Str2FloatClamp() - Clamped 1024 -> 512 (delta = -512) to Range 1..512
INTERNAL ERROR: Can't open file '3DO/Effects/GunShells/GunsmokeI.tga'
WARNING: object '3DO/Effects/GunShells/GunsmokeI.tga' of class 'TTexture2D' not loaded
INTERNAL ERROR: Texture required
WARNING: object '3DO/Effects/GunShells/Cannonsmoke.mat' of class 'TMaterial' not loaded
No spawner for 'com.maddox.il2.objects.vehicles.stationary.Smoke$Smoke24'
No spawner for 'com.maddox.il2.objects.vehicles.stationary.Smoke$Smoke25'
No spawner for 'com.maddox.il2.objects.vehicles.stationary.Smoke$Smoke26'
No spawner for 'com.maddox.il2.objects.vehicles.planes.Plane$A_26B'
Initializing DirectSound playback device...
Primary buffer created.
Playback format is set : sampling rate = 44100, num channels = 2.
Not enought hardware buffers (0), hardware disabled
Buffer caps : Transfer rate = 0, CPU overhead = 0.
Default speaker config is : 1310724.
Direct sound audio device initialized successfully :
DX Version : 7
Hardware - disabled [buffers : 0]
Extensions - enabled :
EAX ver. 1 [ ] - disabled
EAX ver. 2 [ ] - disabled
EAX ver. 3 [ ] - disabled
I3D ver. 2 [ ] - disabled
ZoomFX [ ] - disabled
MacroFX [ ] - disabled
SIMD render [X]
num channels 32
Cannot open audio file samples/infinite 1
Loading mission QuickQMBPro/BAT_Aleutians/BAT_AleutiansBlueNone00.mis...
Y=1940 / M=11 / H= 12 , Temperature - 0m = 2.0 .
Loading map.ini defined airfields:
Load bridges
Load static objects
##### House without collision (3do/Tree/Tree2.sim)
##### House without collision (3do/Buildings/Port/Floor/live.sim)
INTERNAL ERROR: Str2FloatClamp() - Clamped 5 -> 2 (delta = -3) to Range 0..2
INTERNAL ERROR: Str2FloatClamp() - Clamped 2e+006 -> 1e+006 (delta = -1e+006) to Range 0..1e+006
SAS Common Utils Game Version = 4.122
ERROR file: File users/badenov/Icons not found
Mission: QuickQMBPro/BAT_Aleutians/BAT_AleutiansBlueNone00.mis is Playing
warning: no files : music/inflight
[Jul 7, 2018 8:22:25 PM] -------------- END log session -------------
My graphics card is by Intel, a 630, and I am aware that Intel cards aren't fully compatible with Il-2. I have had a problem I've reported in the past, about cloud details, but the problem to hand, the "following box" anomaly (it - or they - are always centered on the player aircraft), only appeared a couple of weeks ago, long after I'd upgraded to 3.3.1, and I'm just not finding the remedy for this. BTW, the problem does appear in all BAT modules, but it's so faint in the TGA career I'm flying that it's barely noticeable against the SCW landscape.
I ought also to add that in addition to my BAT installation, I also have a "stock" 4.13.4 installation on my hard drive, and there's no trace of this anomaly in that version.