Invalid join when using --inner flag

[miroli]

Given:

a.json

{"name":"Fred","color":"red"}
{"name":"Alice","color":"green"}
{"name":"Bob","color":"blue"}

and b.json

{"name":"Fred","number":"21"}
{"name":"Bob","number":"102"}
{"name":"Alice","number":"42"}

the command ndjson-join --inner 'd.name' <(cat a.json) <(cat b.json) outputs:

[{"name":"Fred","color":"red"},{"name":"Fred","number":"21"}]
[{"name":"Alice","color":"green"},{"name":"Bob","number":"102"}]
[{"name":"Bob","color":"blue"},{"name":"Alice","number":"42"}]

Note that it works as expected when the --inner flag is omitted.