@crinrict Just wanted to provide a quick heads up in regards to this bug. I see that based on the insight you have received from the other trouble tickets you believe this may be an issues specifically involving modifications and cheats codes users. I'm not sure this is the case.
I conducted multiple play throughs trying to troubleshoot this same bug within the Entertainment career. I was working specifically on the Comedian path. It appears that the "work bug" happens every time a major event happens in the middle of one of the work shifts.
For example:
The Sim is at level 4 or 5 in the Entertainment path. While at work the sim gets the opportunity to choose between two options; you can choose to take a chance and leave the stage and work your new comedic material for a specific PR Agency, OR you can just do the gig you were already going to do and your career will continue without any significant change. Every time the choice was made to take the make the more obvious choice (The choice to have a significant boost and promotion in the Sims' career) the character will receive various bonuses while at work. This is the exact place where the bug occurs. The Sim gets sent home even though he was still on shift. Almost as if the game thinks you came home from work and received a promotion. Where really you were received a career boost and promotion BUT you still have a few more hours to fulfill during the shift you were already on.
Basically the game is essentially promoting you while you are still on shift. Causing the Sim to get sent home in the middle of the shift. When this happens the Sim will be at home but on the HUD will have options as if the Sim is still at work (Leave Early, Work Hard, Normal etc.) .
No cheats, no mods. Only a number of expansion packs. If additional info is required let me know!