Nios terminal with copy to file inserts white space

I have a nios processor connected via USB blaster to the command line nios2 terminal. This works as expected.

I want to copy the output to a file as well as using the terminal so within the nios command shell I use:
nios2-terminal.exe | tee /cygdrive/c/logfile.txt

This generates the logfile correctly (in C:\Users\<user>\AppData\Local\VirtualStore\logfile .txt), however the output which appears on the terminal has blocks of extra white space in it every few lines of output. Is this normal for other users? I am using Quartus web edition v12.1.