Mhh, reading the createrune docs, that might indeed be the case:

restrictions (one of, optional): It can be the string readonly, or an array of restrictions. Each restriction is an array of one or more alternatives

Will test with v24.11

update: you are right, on v24.11, I need to run this:

$ lightning-cli createrune restrictions='[["method=invoice"]]'

and this throws:

$ lightning-cli createrune restrictions='["method=invoice"]'
{
   "code": -32602,
   "message": "restrictions: not a valid restriction (should be array): invalid token (see logs for details)"
}