I attached a GridInformation component to the tilemap and made the tilemap into a prefab.
But the following error message pops up whenever I modify the prefab and Unity tries to serialize it.

The line below is the code causing the problem.

Not sure how to fix it nor whether it will cause some problems.
I am using Unity 2022.3.20f1 and 2D Tilemap Extras 3.1.2.