Yeah this happens with many airlines.

So most seats upfront or in preferred locations can be blocked.

A good example is CZ with my CI membership they still always block the first 3 rows.

Even in business class B787 where there are only 5 rows in total they still block the 1st 3 rows and so usually you almost have no choice.

Generally there is little you can do apart from turning up earlier at the airport to try and get that preferred seat on check in.