MongoDB disk space increases abruptly - WiredTigerLAS.wt

[zhangruian1997 (瑞安 张)]

I have some question about this case.
when we do a an __wt_las_insert_block ,we can insert some page which is not WT_UPDATE_BIRTHMARK

And when we do __wt_las_sweep，we only delete those page with WT_UPDATE_BIRTHMARK flag

Does it means there always some page can not delete from WiredTigerLAS.wt file? Because i notice that the WiredTigerLAS.wt file size nerver shirnk.