Hello Riyadi, I may or may not merge the inside squares into a bigger relation later. You probably don't need to 'fix' any warning here before consulting to the openstreetmap Data Working Group first

The last time a colleague in your team is trying to 'fix' invalid relation in this area was this https://www.openstreetmap.org/changeset/133693273 and they made the entire forest area into a single residential village that was supposed to be only a coordinate.

This forest project is following example from canada forest import for the square division system, if you would like to add more squares to the remaining forest outline i would appreciate that :)

Thank you,
FenyMufyd