I am giving you the brief description of every type of checkpoints:
Incremental Checkpoint: Incremental checkpointing improves the performance of crash and instance recovery (but not media recovery). An incremental checkpoint records the position in the redo thread (log) from which crash/instance recovery needs to begin. This log position is determined by the oldest dirty buffer in the buffer cache. The incremental checkpoint information is maintained periodically with minimal or no overhead during normal processing.
Partial Checkpoint: When backup of a tablespace in an open database begins, a partial checkpoint is performed by every instance for the datafiles in that tablespace
Full Checkpoint: In a full checkpoint, the database server flushes all modified pages in the shared-memory buffer pool to disk. When a full checkpoint completes, all physical operations are complete, the MLRU queue is empty, and the database server is said to be physically consistent.
Fast_Start_MTTR_Target cause database checkpoint to occur whenever the expected time to recover the instance exceeds 5 seconds. So just check out your database for it.
Hope it will help you.