Reassembling mp4 = slowest version. Wrong frame rate?

### Magick.NET version

Magick.NET-Q8-AnyCPU (11.1.0)

### Environment (Operating system, version and so on)

Windows 10 x64, ubuntu

### Description

Trying to understand the reason of changing speed of output mp4 during just "read file->get frames->reassemble to new mp4".
Partially, this issue relative to https://github.com/dlemstra/Magick.NET/issues/1102.

So the main issue for me is in different speed in output mp4 and i can't understand how it may be fixed from my side.

original mp4 : https://user-images.githubusercontent.com/1579535/163726073-02a4deed-604e-4ade-913a-fc6f6d684e95.mp4

reassembled version with composing : https://user-images.githubusercontent.com/1579535/163726081-2412720a-1aa0-4667-9049-6aa7cd468251.mp4

reassembled version without any additional actions : https://user-images.githubusercontent.com/1579535/163726125-d576c698-f1d0-4e9e-b72a-0c175ae2ab69.mp4

### Steps to Reproduce

I prepared ready-to-run code on github repo to reproduce it : https://github.com/Nigrimmist/MagickFfmpegBugSample (mp4 file included)

Sample code : https://github.com/Nigrimmist/MagickFfmpegBugSample/blob/master/ConsoleApp/Program.cs

I prepared two segments of code, one with using Compose previous frame, one without.

My code execution result is :

Original file (cat.mp4) details (focus on duration) :

Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 122 KiB
**Duration : 6 s 50 ms**
Overall bit rate : 166 kb/s
Writing application : Lavf58.20.100

Output file with composing frames (super slow) :

Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 127 KiB
**Duration : 23 s 800 ms**
Overall bit rate : 43.6 kb/s
Writing application : Lavf59.20.101

Output file without any additional actions during reassembling :

Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 82.4 KiB
**Duration : 9 s 640 ms**
Overall bit rate : 70.0 kb/s
Writing application : Lavf59.20.101

Additional file info properties you can find here : https://pastebin.com/RCHKuVYc. All data got from https://mediaarea.net/'s free/open source soft.

So maybe you have any receipt how it may be "reassembled" without loosing initial speed? Thanks!