Step 1: a pilgrim passes the miqat without ihram.
Step 2: farther on, the pilgrim enters qiran ihram for Umrah and Hajj together.
Result: in the precise described case, al-Quduri states one dam, not two.
The statement is not a general waiver for every ihram violation. A real case may need additional facts on returning to the miqat, remedy and timing.