Often there is a known reason why a company’s general counsel departs—retirement, a better job or simply dismissal. But when a GC leaves abruptly and without a stated reason, it should set off little alarm bells for the board of directors, according to corporate governance experts.

Abrupt departures do happen, such as the hasty exit of general counsel Dane Butswinkas from Tesla Inc. on Feb. 20 after only two months on the job.