The generic-polish trap
The most common failure mode is a video that's technically well-made and totally interchangeable. The b-roll is sharp, the color grade is clean, the music is a generic uplifting cue. The CEO says some version of "we're passionate about quality." Nothing in the video would be wrong if you swapped the company logo for a competitor's. That's a failure even if every shot is technically good.
The pre-production gap
This happens because most production companies are paid to produce, not to ask hard questions about what makes the company different. They ask "what's your brand voice" and get a deck back. They don't sit down with the founder and ask "if your biggest competitor disappeared tomorrow, what would you actually miss about competing with them?" The answers to those harder questions are what make a video specific.
The wrong subject on camera
Default casting is "put the CEO in front of the camera." Often the CEO is the worst person to interview, especially for operational businesses. The plant manager, the lead designer, the customer service lead, the founder's first hire from 12 years ago: any of them is usually a better camera subject than the C-suite. The most-quoted line in a brand film is rarely the executive's.
Treating the camera like a reporter, not a tool
The other big failure: treating the camera as an external observer who's there to capture what's already happening, instead of as a tool that can produce something specific. Good documentary brand work happens when the team has a clear thesis going in and uses the camera to prove or disprove it. "Let's just shoot a day in the life and see what we get" almost never works.