It is extremely disappointing for an employee to be socially isolated at the workplace. He/she begins assuming that it is his/her wrongdoing and that he/she must have a fatal flaw if others are trying to stay away from you. You begin questioning yourself and start doubting your own abilities. However, the victim of bullying must know that this is what bullies do. They try to create a toxic atmosphere at the workplace and choose not to call you group meetings or lunches to make you feel bad about yourself.
It is a worrying sign because social isolation takes place in the initial stages of bullying. Their behaviour becomes even more abusive and hurtful in the coming weeks and months and the isolation becomes outright ridicule very quickly. It is important that you speak up against it and ask your peers what is wrong and clear any misunderstanding that exists.