What's up with misleading job descriptions?

I'm job searching and I came across a positions that sounds pretty cool. The job description already has over 20 bullet points that all seem really engaging. I'm down to work but the cherry on top is this:

"This job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice. "

Shouldn't job descriptions be a comprehensive list of duties or am I misunderstanding? Is this red flag?

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