Is it a sign of job insecurity to check your mobile constantly even on work breaks?

Individual Answer. If you are asking if there is a universal correlation the answer is no. Because you are connecting "job insecurity" and "checking your mobile constantly" there might be a correlation for you. It's worth looking into, job insecurity is not a pleasant thing to live with, and if there is something you can do about it you should take it on consciously. Best wishes to you.
Probably Not. Checking your mobile constantly on work breaks may be a habit, may stem from not wanting to "miss out" on something important, or some other reason. Job insecurity is probabpy not a common reason why a person checks his or her mobile during work breaks.