I have somehow killed any post from me with "ping" in the subject

Here's an odd one.

Whenever I post an article with the word "ping" in the subject line (or
"PING", "Ping", etc - any combination of upper/lower case), it immediately
goes into my kill file. But other people posting articles with that word
in the subject is not killed.

I checked my filters file and noticed a number of rules that had the
word "ping" ("PING", etc) in the subject, usually in combination with
other words or names. I removed all of them, but it still behaves the
same way.

Anyone know why this might be happening, or what I should look into?

Thanks,
Joyce Wermont