[Bender]

    for  i in $(seq 100);do echo -en '0';done
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

    test            69s     in      txt     "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000" "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000" "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"

    nsd-checkzone nochan.net ./nochan.net.zone
    zone nochan.net is ok

    nsd-control reload nochan.net
    ok

    # from my laptop
    dig -t txt +short test.nochan.net
    "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000" "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000" "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"

Still shows up as three quoted strings 100 characters long each but not 300 0's meaning no concatenation at least not when using dig which is what this thread is about.