Yes – the latest release (4.22.4) should recognize CSV files during upload.
For each line in a CSV the first keyword is considered the “original” keyword and the rest are the synonyms added to it.
Can I take a look at this somewhere? Please add temporary back-end and FTP details, I will debug the code if needed.
I just tested on all of our local and remote test servers, and it seems to work all right. It can be a 3rd party script conflict of some sort.