Yeh
Well...
They've been trying to fix it ever since then without much luck so far. Heck, they even took the Torchbugs and Deer out of Cyro in an attempt to fix it.
Supposedly in the coming base patch they are halving the LOS checks on skills in yet another try. Guess we'll see.

Personally, I think it's somewhere back in the code with those patches you listed and they have no real idea what or why or how to fix it.
All we can do is cross our fingers and hope this one does the trick.

In Battlefield when this happened (huge lag spikes, odd server interactions), friends and I played "Let's find the Brazilian".

I can't help but wonder if tuning the usersettings.txt graphics down would have anything to do with decreasing the packet size sent on drawing the data? The drawing of shadows in particular.
(probably not, but here's hoping anyways)

I figured I would post my usersettings file here:
(Also feel free to inform me of anything I'm doing wrong or can tweak, but I am getting pretty decent performance & would suggest to anyone to try some of these tweaks)

SET MouseRawInput "1"
SET MouseSensitivityFirstPerson "0.50000000"
SET MouseSensitivityThirdPerson "0.86000001"
SET MouseSmoothing "0"
SET InvertMouseWheel "1"
SET InvertMouseY "1"
SET InvertMouseX "1"
SET MAGELIGHT_LIGHTS_VISIBLE "1"
SET PFX_SUPPRESS_DISTANCE_v2 "10.00000000"
SET PFX_GLOBAL_MAXIMUM "168"
SET MULTI_GPU_CHECK "1"
SET CachedRLREnabled "1"
SET CachedReflectionResolution "4"
SET CachedShadowFiltering "3"
SET ScreenshotFormat.2 "JPG"
SET PregameGammaCheckEnabled "0"
SET HardwareCheckEnabled.3 "0"
SET SUB_SAMPLING "2"
SET REFLECTION_QUALITY_v3 "2"
SET PARTICLE_DENSITY "3"
SET HIGH_RESOLUTION_SHADOWS "0"
SET SHADOWS "1"
SET GAMMA_ADJUSTMENT "119"
SET VIEW_DISTANCE "0.95999998"
SET GPUSmoothingFrames "0"
SET MIP_LOAD_SKIP_LEVELS "0"
SET RAIN_WETNESS "0"
SET LENS_FLARE "1"
SET GOD_RAYS_v2 "0"
SET ANTI_ALIASING_v2 "1"
SET AMBIENT_OCCLUSION "0"
SET COLOR_GRADING_v1 "0"
SET BLOOM "0"
SET DEPTH_OF_FIELD "1"
SET TONE_MAPPING "1"
SET COLOR_CORRECTION "0"
SET SOFT_ALPHA "0"
SET DISTORTION "0"
SET CHARACTER_LIGHTING "0"
SET DIFFUSE_2_MAPS "0"
SET DETAIL_MAPS "0"
SET NORMAL_MAPS "0"
SET SPECULAR_MAPS "0"
SET CLUTTER_2D "0"
SET SIMPLE_SHADERS "0"
SET WATER_FOAM "0"
SET VSYNC_INTERVAL "1"
SET VSYNC "0"
SET MAX_ANISOTROPY "3"
SET PreferMaximizedWindow "0"
SET PreferExclusiveFullscreen "0"
SET FULLSCREEN_v5 "1"
SET FullscreenHeight "1080"
SET FullscreenWidth "5760"
SET WindowedHeight "768"
SET WindowedWidth "1024"
SET FOVChangesAllowed "1"
SET AgreedToPEGI "1"
SET VoiceChatAutoJoinChannels.2 "0"
SET VoiceChatEnabled.3 "1"
SET LuaMemoryLimitMB "512"
SET GamepadSensitivityFirstPerson.2 "0.72000003"
SET GamepadSensitivityThirdPerson.2 "0.85000002"
SET GamepadInvertX "0"
SET GamepadInvertY "0"
SET GamepadVibrationEnabled "1"
SET SOUND_ENABLED "1"
SET FOOTSTEPS_VOLUME "60.00000000"
SET FOOTSTEPS_ENABLED "1"
SET SPEAKER_SETUP "0"
SET BACKGROUND_AUDIO "0"
SET VO_VOLUME "60.00000000"
SET VO_ENABLED "1"
SET UI_VOLUME "60.00000000"
SET UI_ENABLED "1"
SET AMBIENT_VOLUME "60.00000000"
SET AMBIENT_ENABLED "1"
SET SFX_VOLUME "60.00000000"
SET SFX_ENABLED "1"
SET MUSIC_VOLUME "30.00000000"
SET MUSIC_ENABLED "1"
SET AUDIO_VOLUME "30.00000000"
SET AUDIO_ENABLED "1"
SET TooltipFilter "-1"
SET TooltipNumOptions "2"
SET Language.2 "en"
SET GraphicsDriver.7 "D3D11"
SET PatchDataPath "game:/GameData/"
SET CacheDataPath "machine:/Cache/"
SET ViewedAddOnEULAVersion "5"
SET AcceptedAddOnEULAVersion "5"
SET AcceptedCodeOfConductVersion "1"
SET AcceptedPrivacyPolicyVersion "2"
SET AcceptedTOSVersion "1"
SET AcceptedEULAVersion "3"
SET DirectionalDamageIndictorVisibleInThirdPerson "0"
SET CameraFramingTransitionEnabled "1"
SET SkipPregameVideos "0"
SET HasPlayedPregameVideo "1"
SET RangedKillCamera "0"
SET PlayerKillCamera "1"
SET LastMonsterKillCamera "1"
SET MinFrameTime.2 "0.01000000"
SET ParticlesEnabled "1"
SET RequestedNumJobThreads "-1"
SET RequestedNumWorkerThreads "-1"
SET FreeUnusedGrannyFileSections.2 "0"
SET IsTrustedMachine "1"
SET RememberAccountName "0"
SET AccountName ""
SET LastRealm "NA Megaserver"
SET CustomUIScale "0.97222197"
SET UseCustomUIScale.2 "1"
SET RollDodgeDoubleTapEnabled "1"
SET RollDodgeDoubleTapTimeWindow.2 "185"
SET ClampGroundTargetEnabled "1"
SET MonsterTellsEnabled "1"
SET CameraZoomDistancesSynced "1"
SET SiegeCameraZoomDistance "9.00000000"
SET WeaponsOutCameraZoomDistance "8.50000000"
SET WeaponsSheathedCameraZoomDistance "8.50000000"
SET MaxNetworkWriteBuffer "15728640"
SET MaxNetworkReadBuffer "10485760"

Point is flying is right they broke it even more at some point and have yet to fixed it.... Absolutely unacceptable for any business and any real company that has plans to not go under anytime soon would address this issues right away because of the longevity of their brand. Think of a bank atm had this problem. *** whether it was hardware or software fixed in a couple days. What about a cable company people lots of us dislike. Even when it takes them a week to fix my internet or anything else and I'm pissed it took them that long and threaten to change services. But zos they get away with well doing almost nothing. Your business model is failing FIX IT HIRE OUTSIDERS TO FIX YOUR CODE. Bf4 is still going because they fixed their product.... Yet Zenimax sits around putting new content to a broken game. At this point it's funny

I would really like to hear a statement from ZOS on whether or not my theory is credible or not and whether or not it has been looked into yet or if there are plans to look into it.

I've figured just as much, it must've started at some point because I clearly remember PvP'ing for hours and days with no sleep, just passing out occasionally and I've never had a single lag at that time shortly after the launch. now I don't even bother entering Cyro bcuz of all the lag and choppiness.

Lol I player location only effects the player. It doesn't cause the servers lag.