Answer
Use ? instead of & before the first parameter in the Quick Report URL address: ifsrep:qr.<report_id>?MARKET_CODE=$MARKET_CODE$ (using $...$ to substitute the Lobby's own parameter value) — using & for the very first parameter in that URL breaks the address parsing entirely, which is why the report failed to open at all when that was tried; switching just that first separator to ? resolves it while keeping the same lobby-parameter substitution syntax.