This sort of thing has been happening for a while. Apparently DF-11 and DF-15 are due to be retired soon so PLARF have been setting them off like firework whenever they get an excuse. Most commonly just before a new batch of recruits graduate from their training they get an opportunity like this to launch a real missile.
Let's hope half of those are used for interception practice. Would be a great opportunity for some more real life verification of training.