Steps to Reproduce: Deploy the attached VDB and DS.
Workaround: Workaround Exists
Workaround Description: Dived the SQL up as shown in Quote and GetQuote.
project_key: SOA

That attached VDB is invoking the yahoo quote service.  Invoking the BrokenQuote procedure like this:

Exec VGetQuote.BrokenQuote('IBM');
 results in the following exception:

Remote org.teiid.api.exception.query.QueryPlannerException: Source command "EXEC GetQuote.invokeHttp('GET', null, concat('?f=snd1l1&s=', VGETQUOTE.BROKENQUOTE.Ticker))" contains non-pushdown constructs. 

The GetQuote and Quote procedures divide the SQL from BrokenQuote into two procedures and does not produce the exception, but I don't see why BrokenQuote does not work.