While not technically in violation of the OpenAPI specification, including a query parameter in a path should be flagged as an error in Spectral:

A path has specific meaning in HTTP as a part of a URL that comes after the host name and before the query string or fragment. A "path item" key must be only a path, it cannot have a query string or a fragment.

For example, the following when def

Test Data:

[
   "first",
   "second",
   "third",
   "forth",
   "fifth"
]

Selector:

$[*,1]

Resul:

Unable to parse token *,1 in expression: [*,1]

Expected result (Proposal A):

[
   "first",
   "second",
   "third",
   "forth",
   "fifth",
   "second"
]

https://cburgmer.github.io/json-path-comparison/results/union_