Malaysia - International Stamps on Domestic Mailing

International stamps were first on sale in Kedah on Oct 3, 2016 and in Penang on Oct 4, 2016 due to holidays. I took opportunity to mail on Oct 3 in both Kedah and Penang these postcards using international stamps, with Sungai Petani First Day Cover cancellation, for domestic mailing - wondering if Pos Malaysia will reject them outright or still deliver. Fortunately, both postcards still got cancelled and delivered to add a philatelic history in my collection.

Postcard 1
Mailed from Sungai Petani Post Office on Oct 3, 2016.

Postcard 2

Mailed from a street mailbox in Seberang Jaya, Penang Mainland near the Swimming Pool. Oct 3, 2016 was a holiday in Penang.