I've been in my position for several years now. Over the years, I've noticed how inept my employer can be at retaining employees and also making sure there's enough staff scheduled to meet client needs, and if the client doesn't pay for enough staff, instead of negotiating, they just go with it and expect others to pick up the slack.
Right now my issue is that for months, I've been expected to do all the duties associated with my job, then at a certain time of day, switch over to the same job but with a different client, and do that job. So far so good.
Except that for several hours mid shift, I'm actually expected, regardless of which job I'm assigned to at that time of day, to do both jobs, and often a third job which is not my position and which has a different rate of pay, all at the same time.
In fact, my boss got mad at me today, despite the fact that it was discussed several weeks prior that I'm going back to school so my hours need shifted around, we came up with a new schedule, etc…and the schedule has been up for at least a week for said boss to notice that I won't be able to just take over and do three jobs like usual at the same time to cover up for the company so the client doesn't realize we can't possibly meet their needs with the amount of staff they let us have for that project.
They actually got irritated with me for finding someone to oversee the project while I'm gone for class for a couple hours, because that person won't be doing the extra work I do, just overseeing the one person who actually is supposed to be doing that job while they do it, letting them go on breaks, etc.
TLDR: My boss and the company we work for both routinely expect me to cover up for the fact that we don't have enough staff, by doing the work of three different jobs at the same time, and only getting paid for the one I'm technically clocked-in under.