Table with hash partition contains partition with 0 rows

We have a hash-partitioned table with 256 partitions. I was expecting that these partition will contain around even number of rows. but some of them have 0 rows.

A. Is this expected/normal?

B. If not, what could've caused this and how can we fix this?

We are facing performance issue on query that is accessing this table so we need to check if this might be one of the causes.

Attached below is a spreadsheet of row distribution on each partitions.

Thanks.