AWS DMS Source Mongo DB target PostgreSQL change data type in transformation rule

I am running a DMS migration task,

• Source - Mongo DB
• Target - Postgres SQL

One of the integer field in mongo has 5% values in string and rest values in integer data type. After migration to Postgres the String values is as it is and all integer values in that column becomes null.

I also tried adding a transformation rule where I changed that column data type to int2, int4, string but still only 5% data comes with changed data type but rest of values are NULL which were integer type in mongo DB.

How will I be able to change all values to Integer type or all to string type. As I do not want to lose any data.