Warming in order page

Hi First of all , i just want to say thank for the great plugin, everything is great ! just in view order page , there have a warning below

Warning: Undefined array key “order-received” in?/wp-content/plugins/qr-code-tag-for-wc-from-goaskle-com/lib/qrct/QrctWp.php?on line?1376

can you kindly let me know if can fix it ?

thank and regards

Mango