--json flag gives ERROR (invalid command)

[MathijsNL]

On a Minecraft 1.13.1 map,

NBTUtil.exe --path=r.0.0.mca --json=test.json
/NBTEdit/r.0.0.mca: ERROR (invalid command)
/NBTEdit/r.0.0.mca: OK
Operation complete.  Nodes succeeded: 1  Nodes failed: 1

Printing works just fine

 + r.0.0.mca
   + Chunk [1, 0]        in world at (1, 0)
   | + Level: 16 entries
   | | + xPos: 1
   | | + zPos: 0
   | | + InhabitedTime: 0
   | | + LastUpdate: 29
   | | + Status: carved
   | | + Entities: 0 entries
   | | + Lights: 16 entries
   | | | + 480 entries
   | | | | + 3440
   | | | | + 3424
   | | | | + 3696
   | | | | + 3680
   etc...