Spam sent to contact address

[Tor User <toruser@xxxxxxxxxxxxxx>]

I am running a tor server and publish a contact email address in a
mangled format, along the lines of  toruser-at-gmail-dot-com. I
have received two apparent spams to that address recenly. A somewhat
surprising aspect is that both contained just one random word and no
other content. They were the only two emails ever received at that
address, and I have not published the address anywhere (although google
finds it at moria.seul.org:9031).

I am wondering whether to put this down to the incopetence of the
spammer(s), or whether there could be any possible reason for why they
might have wanted to send me content-free messages after going into the
effort of unscrambling the email address. I doubt they would have
wanted to learn anything from an automated bounce message (which they
would expect to come from gmail in any case) but cannot see any other
explanation.

Do others also get spam to addresses published only through tor status,
does said spam look like the usual sort of spam, and can anyone think
of an explanation for the above? Many thanks.