The boss I had lied about me multiple times, exaggerated normal incidents to paint me in a bad light, and did everything she could to make me look bad. I raised my concerns to her boss and HR, but they gave no response. There were initially multiple red flags, such as her screaming at me after a miscommunication resulted in me doing a certain training too early and I pointed out how she could've instructed me more clearly, her rescheduling multiple times and never ultimately meeting with me about concerns I had about another employee, and ____. Then all of a sudden, she put me on a PIP. She and the HR rep cited a laundry list of reasons. Several of the points were entirely fabricated, several others were extremely exaggerated, and the remaining ones were things I didn't realize was an issue (such as ____), and that she had multiple opportunities to correct me on before but never said they were a problem. When I tried to say this, they told me that "this isn't a discussion" and that I was "being defensive". I did my best to follow their improvement plan, which included subjective goals like "listening better". I was initially successful with the PIP, but then they assigned me a task which they admitted I was the first on the team to try something like that. I worked on it for several weeks and made steady progress, but they still claimed that I didn't finish fast enough and assigned it to a more experienced team member, and used that as justification to fire me. I checked in with the team member they assigned it to, and although they said the other employee had tried something different that fixed the problem, I confirmed with the employee directly that the had not in fact fixed it and had tried the exact same approach I was doing. To summarize, my boss and the HR team lied multiple times and tried to find any excuse to fire me.
This appears to be a repeating issue with this specific boss, as another intern decided to not return because of her.
Concerning the company overall, the only criticism I have is that there's a vast discrepancy between teams. Some teams have good bosses and some teams have terrible ones. Aside from my boss, the workload and expectations on my team was very light, whereas a different team regularly works late into the night and on weekends.