ffmpeg - Why does concatenating .ts videos through .txt fail from \folder\ but work from \folder\subfolder\? - ffmpeg

Question

I have a bunch of .ts videofiles that I want to merge into a single file so I can convert it to a .mp4 video.
The .ts files are in a folder "E:\videotest" like:
E:\videotest\0.ts
E:\videotest\1.ts
[...]
E:\videotest\100.ts
I used a PowerShell command to output the filepaths in a .txt file:
foreach ($i in Get-ChildItem .\*.ts) {echo "file '$i'" >> mylist.txt}
The resulting mylist.txt looks like:
file 'E:\videotest\0.ts'
file 'E:\videotest\1.ts'
[...]
file 'E:\videotest\100.ts'
When I run the command:
ffmpeg -f concat -safe "0" -protocol_whitelist "file,http,https,tcp,tls" -i "E:\videotest\concat\mylist.txt" -c copy "E:\videotest\concat\combined_video.ts"
I get the error:
Line 1: unknown keyword ' ■f'
E:\videotest\concat\mylist.txt:
Invalid data found when processing input
But if I add a subfolder layer to the files like this:
E:\videotest\0\0.ts
E:\videotest\1\1.ts
[...]
E:\videotest\100\100.ts
And change mylist.txt to:
file 'E:\videotest\0\0.ts'
file 'E:\videotest\1\1.ts'
[...]
file 'E:\videotest\100\100.ts'
The same ffmpeg command will work and create the combined_video.ts file.
Why does converting work with the subfolder structure but not from the main folder?
How do I adjust the ffmpeg command to make it work?
Thank you.

Answer 1

It turns out that the problem was the encoding of the "mylist.txt" file. For some reason it was encoded as "UCS-2 LE BOM". After setting it to "UTF-8" I was able to concatenate the files.