Unexpected error when using "cross apply openjson" with a join - sql

Question

If cross apply is used for a function, but the query also uses a join, how does SQL determine which records to use for the function?
I have a table which contains some JSON strings, and I'm using OPENJSON to parse them. I'm also using a join to determine which records to pass to the OPENJSON function. However, it is erroring on records that aren't in the selection
eg in this example, I am adding two json strings to a table, one of which is good, and the other is truncated. I'm then trying to parse the good row using openJSON, but it is failing on the bad row, even though it isn't being selected...
--create table to store JSON strings
declare #jsontable table (id int identity,
JSONstring nvarchar(2000))
--add one good row, and one bad row
INSERT into #jsontable (JSONstring)
values
('{"RowNumber":1,"Field1":"Hello","Field2":"World"}'), --First row good
('{"RowNumber":2,"Field1":"Hello"') --Second row truncated
--create table with ID of the good record
DECLARE #IDsToSelect table (id int)
INSERT into #IDsToSelect (id)
values
(1)
--parse the json in the good record
select * from #jsontable jst
inner join #IDsToSelect its
on jst.id=its.id
cross apply openjson(jst.JSONstring)
The above example gives a 'JSON text is not properly formatted' error, and it fails because of the bad JSON in row 2, even though I'm only joining to row 1.
Does SQL apply the openjson function to the entire #jsontable table, and then apply the inner join to those results? If so, how should I structure this query so that it only parses the JSON of the selected row?