Calendar View Issues

Hi, we are using the latest version of Chrome. We have calendar which displays our technicians' names and their appointments. I have several of my user reporting that the calendar sporadically does not display some of the technicians' names on their view, using the latest Chrome version, while others can see all the names. Any ideas on why this can be happening? It's coming from the same source data and the same programmed calendar view, so I am at a loss. Any suggestions would be appreciated.