Dump MySQL table to csv file (utf8mb4_unicode_ci)
The CSV "de facto standard" allows for fields to contain line breaks. So, what you get is the result of some of your data in your original table containing line breaks.

When that's the case, one record uses more than one row of text. 

Some libraries or some programs can handle and interpret that adequately, but not all do. For instance, you can use MS Access, and it will work; but if you try MS Excel, line breaks within a field won't be properly handled. If you work with MySQL or PostgreSQL, they can import/export CSV with line breaks in fields.

Check, for instance, Comma-separated values at WikiPedia or RFC 4180


  Fields with embedded line breaks must be quoted (however, many CSV implementations do not support embedded line breaks).