So we only have 2 technical or operation people leaving, since it seems to be relatively at the same time, in my opinion, there was likely some internal conflict in the organization. But reason for employees leaving isn't going to be provided. That is private. You'll have to go to the employee for the answer because companies never public divulge that info.
2 people leaving after a couple years of working isn't abnormal. I work for a multi billion dollar private firm. Our turnover is crazy high. They either can't handle the pace of work and responsibility and get fired or they leave because they want an easier job that requires less of their time.