Major Description
Due to the way Tephra clones mutations, by default the mutation will be set to not write to the WAL.
txPut.setWriteToWAL(put.getWriteToWAL());
Because getWriteToWAL() returns false when durability is USE_DEFAULT (the default durability), the setWriteToWAL will use false (this is arguably not so good on HBase's part - not sure if they got grief for this in the past).
If the mechanism is change to not use these deprecated methods, it will work correctly:
txPut.setDurability(put.getDurability());