N1QL: Wrong span shown in explain for NOT queries

Query which gives correct result:

explain SELECT COUNT FROM simple_table WHERE ((decimal_field1 < 4938) OR ((decimal_field1 > 4938) OR (decimal_field1 <= 4938))) ;

Output:
[
{
"plan": {
"#operator": "Sequence",
"~children": [
{
"#operator": "DistinctScan",
"scan": {
"#operator": "IndexScan",
"covers": [
"cover ((`simple_table`.`decimal_field1`))",
"cover ((meta(`simple_table`).`id`))"
],
"index": "simple_table_idx_decimal_field1",
"keyspace": "simple_table",
"namespace": "default",
"spans": [
{
"Range":

{ "High": [ "4938" ], "Inclusion": 0 }

},
{
"Range":

{ "Inclusion": 0, "Low": [ "4938" ] }

},
{
"Range":

{ "High": [ "4938" ], "Inclusion": 2 }

}
],
"using": "gsi"
}
},
{
"#operator": "Parallel",
"~child": {
"#operator": "Sequence",
"~children": [

{ "#operator": "Filter", "condition": "((cover ((`simple_table`.`decimal_field1`)) < 4938) or ((4938 < cover ((`simple_table`.`decimal_field1`))) or (cover ((`simple_table`.`decimal_field1`)) <= 4938)))" }

,

{ "#operator": "InitialGroup", "aggregates": [ "count(*)" ], "group_keys": [] }

]
}
},

{ "#operator": "IntermediateGroup", "aggregates": [ "count(*)" ], "group_keys": [] }

,

{ "#operator": "FinalGroup", "aggregates": [ "count(*)" ], "group_keys": [] }

,
{
"#operator": "Parallel",
"~child": {
"#operator": "Sequence",
"~children": [
{
"#operator": "InitialProject",
"result_terms": [

{ "expr": "count(*)" }

]
},

{ "#operator": "FinalProject" }

]
}
}
]
},
"text": "SELECT COUNT FROM simple_table WHERE ((decimal_field1 < 4938) OR ((decimal_field1 > 4938) OR (decimal_field1 <= 4938))) ;"
}
]

Query which gives wrong result:
explain SELECT COUNT FROM simple_table WHERE NOT ((decimal_field1 < 4938) OR ((decimal_field1 > 4938) OR (decimal_field1 <= 4938))) ;

{
"plan": {
"#operator": "Sequence",
"~children": [
{
"#operator": "IndexCountScan",
"covers": [
"cover ((`simple_table`.`decimal_field1`))",
"cover ((meta(`simple_table`).`id`))"
],
"index": "simple_table_idx_decimal_field1",
"keyspace": "simple_table",
"namespace": "default",
"spans": [
{
"Range":

{ "High": [ "4938" ], "Inclusion": 3, "Low": [ "4938" ] }

}
],
"using": "gsi"
},
{
"#operator": "IndexCountProject",
"result_terms": [

{ "expr": "count(*)" }

]
}
]
},
"text": "SELECT COUNT FROM simple_table WHERE not ((decimal_field1 < 4938) OR ((decimal_field1 > 4938) OR (decimal_field1 <= 4938))) ;"
}
]

Query which gives wrong result:
SELECT bool_field1 FROM simple_table WHERE (bool_field1 == true) AND (bool_field1 == false)
[
{
"plan": {
"#operator": "Sequence",
"~children": [
{
"#operator": "IndexScan",
"covers": [
"cover ((`simple_table`.`bool_field1`))",
"cover ((meta(`simple_table`).`id`))"
],
"index": "simple_table_idx_bool_field1",
"keyspace": "simple_table",
"namespace": "default",
"spans": [
{
"Range":

{ "High": [ "*true*" ], "Inclusion": 3, "Low": [ "*true*" ] }

}
],
"using": "gsi"
},
{
"#operator": "Parallel",
"~child": {
"#operator": "Sequence",
"~children": [

{ "#operator": "Filter", "condition": "((cover ((`simple_table`.`bool_field1`)) = true) and (cover ((`simple_table`.`bool_field1`)) = false))" }

,
{
"#operator": "InitialProject",
"result_terms": [

{ "expr": "cover ((`simple_table`.`bool_field1`))" }

]
},

{ "#operator": "FinalProject" }

]
}
}
]
},
"text": "SELECT bool_field1 FROM simple_table WHERE (bool_field1 == true) AND (bool_field1 == false) ;"
}
]