Created a table named NUMBERS with NUM_CLOB column of the type CLOB, whenever a change record is produced, this field contains the value "null" in the payload.

For example,

update numbers set num_clob = 'yossi';

Is represented:

\"after\":{\"NUM_ID\":22,\"NUM_INT\":1,\"NUM_BIGINT\":1,\"NUM_SMALLINT\":1,\"NUM_FLOAT\":11.103,\"NUM_REAL\":9.15,\"NUM_DOUBLE\":10.52,\"NUM_NUMERIC\":\"Cw==\",\"NUM_TS\":1632722730524701,\"NUM_CLOB\":null}

According to the documentation, this type is supported and should be treated as String.