JSON for "type bits" in YANG models not handled correctly

We have a section with flags in one of our models, like this:

leaf lrs-bits {
type bits {
bit lookup

{ description "Lookup bit."; }

bit rloc-probe

{ description "RLOC-probe bit."; }

bit strict

{ description "Strict bit."; }

}
description
"Flag bits per hop.";
}

I'm trying to use RESTCONF to set more than one bit. However, if I use an array, only the last one mentioned is actually set:

"hop": [

{ "address": "192.0.2.1", "lrs-bits": ["lookup", "rloc-probe", "strict"] }

,

{ "address": "192.0.2.2", "lrs-bits": ["lookup", "rloc-probe"] }

,

{ "address": "192.0.2.3", "lrs-bits": ["lookup", "rloc-probe", "strict"] }

]

That is, when I read back the restcnf entry, only "strict" is set for the first hop, "rloc-probe" for the second hop, and "strict" for the last hop. I tried a few different combinations, but all were rejected.