Fill handle and cell dragging & dropping

Hi, I sometimes having problem with my MS office (for MAC) (365 subscribtion) Excel, not able to Fill handle and cell dragging & dropping on a particular column but workable on the other columns next to it despite, I have made sure all the settings are correct. A friend of mine suspected a bug in my Excel and advised me to zoom out that particular page and I tried and it worked perfectly. However, my main question is there anyway to have this bug removed permanently from my Excel enable to use my Excel normally? 

I would appreciate if anyone can help me solve this issue.