Issue with built-in GM functions, performance decrease after multiple uses

Hello,

Im making a roguelike topdown, and i've built a level editor for that purpose.
Im using ds_list_write and ds_grid_write with buffer _save to save those map, and ds_list_read + ds_grid_read and buffer_load to loead them.

I've witnessed a very problematic issue : loading time increase exponentially with the amount of map i have to load. To the point loading times reach unbearable value with not so much maps to load.

Using current_time and show_debug_message with a delta of...

Issue with built-in GM functions, performance decrease after multiple uses