My preview window looks fine in vegas both during editing and rendering but the final video file has weird artifacts occurring, almost looks like compression. It occurs at about the 0:06-0:08 mark.
I'm using Magix AVC/MP4 on the Internet UHD 2160p 59.94fps (NVIDIA NVENC) template.
Which Program and buildnr is used and show here the MediaInfo of that exported outcome. How to give here that Info look here: https://www.vegascreativesoftware.info/us/forum/faq-how-to-post-mediainfo-and-vegas-pro-file-properties--104561/
Vegas 17.0 build 452
General
Complete name : C:\Users\Alex\Documents\render artifacts.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/mp42)
File size : 96.4 MiB
Duration : 21 s 255 ms
Overall bit rate mode : Variable
Overall bit rate : 38.0 Mb/s
Encoded date : UTC 2020-09-23 13:53:48
Tagged date : UTC 2020-09-23 13:53:48
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L5.2
Format settings : CABAC / 1 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 1 frame
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 21 s 255 ms
Bit rate : 37.9 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.940 (60000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.076
Stream size : 95.9 MiB (99%)
Language : English
Encoded date : UTC 2020-09-23 13:53:57
Tagged date : UTC 2020-09-23 13:53:57
Codec configuration box : avcC
Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 21 s 248 ms
Bit rate mode : Variable
Bit rate : 192 kb/s
Maximum bit rate : 316 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 491 KiB (0%)
Language : English
Encoded date : UTC 2020-09-23 13:53:57
Tagged date : UTC 2020-09-23 13:53:57
Try rendering without using NVENC. Do a CPU only render and see if there is a difference.
Did you a default render with that template or customized?
If I render 4K to that template on my laptop from signature I get a bigger file with higher bitrate.
Which is your Nvidia GPU and which exact driverversion is installed for that GPU?
Rendering with the same template but without Nvidia NVENC resulted in the issue not occurring, going to try updating drivers on the card and see if it persists (it probably will since im usually on top of those updates)