Warning! SCAM in your DMs
Above are screenshots of a DM I received yesterday. I replied hello back, and they sent me the above message.
Their next step in this scam is to direct you to a Discord to "clear it up", wanting you to DM a discord account who begins asking you questions before ultimately asking you to change your email address to theirs so they can ‘fix’ the flag on your account. Then they lock you out of your account (I'm assuming on Discord) then they log in as you, and start sending anyone and everyone the same "I accidentally reported you" message from your account.
I reported this account through the Tumblr support form, it is a phishing scam. If you get a message like the one above from any account, report the account and let Tumblr know you are reporting phishing.