Below is the Input CSV file which when after doing a sort and doing an export-csv , the format of the out does not looks good when opened.
$FileLogdate = (Get-Date -f yyyy-MM-dd_HH-mm-ss)
# Inputfile
"{0}`t{1}`t{2}" -f "COne","CTwo","CThree" | Out-File -Append $PSScriptRoot\testtrycsv_$FileLogdate.csv
"{0}`t{1}`t{2}" -f "C1R1","C2R1","C3R1" | Out-File -Append $PSScriptRoot\testtrycsv_$FileLogdate.csv
"{0}`t{1}`t{2}" -f "C1R1","C2R1","C3R1" | Out-File -Append $PSScriptRoot\testtrycsv_$FileLogdate.csv
"{0}`t{1}`t{2}" -f "C1R2","C2R2","C3R2" | Out-File -Append $PSScriptRoot\testtrycsv_$FileLogdate.csv
"{0}`t{1}`t{2}" -f "C1R1","C2R1","C3R1" | Out-File -Append $PSScriptRoot\testtrycsv_$FileLogdate.csv
# Output file
"{0}`t{1}`t{2}" -f "COne","CTwo","CThree" | Out-File -Append $PSScriptRoot\test-temp.csv
$input = "$PSScriptRoot\testtrycsv_$FileLogdate.csv"
$inputCsv = Import-Csv $input | Sort-Object * -Unique
$inputCsv | Export-Csv "$PSScriptRoot\test-temp.csv" -NoTypeInformation -delimiter "`t"
below is input csv file
Below is the output format of the export-csv view when opened
When looking the export-csv in Notepad++ , it looks like this



I actually cannot reproduce the behaviour you're having. Let's create your input data ...
When we output this input data it looks like this:
Now let's sort your input data ...
When we output this sorted input data it looks like this:
Now let's export these sorted data to a file in the current working directory using a
<tab>as delimiter ...And the output of that looks like this ...
¯\_(ツ)_/¯