I suggest taking a look at your html sanitization settings make sure html isn't allowed in markdown settings.
Next step would be to move the other 2 topics from that category and check if you still see broken markup.
I had installed nodebb newly on ubuntu 14.04 along with mongodb.
During the setup process no option was given to setup admin user/login. But, it looks to have created an admin with username "admin" but the password is unknown.
Could you please help how I can get the admin password?
@smogulur the security of NodeBB makes it impossible to retrieve a password. This is by design. If you haven't gotten too far as far as installation goes, you should drop the database you chose and restart.