Is it permissible to marry a girl who suckled with the maternal uncle, knowing that the maternal uncle suckled with the girl's mother?

There is no impediment to marrying the girl if she was nursed with your maternal uncle by her mother or by a foreign woman; she is not forbidden to you. However, if she was nursed by your maternal uncle's mother (your maternal grandmother), then she becomes your maternal aunt through suckling, and it is forbidden for you to marry her, due to the saying of the Prophet, peace and blessings be upon him: "Suckling prohibits what lineage prohibits." As for your maternal uncle suckling with the girl's mother, no prohibition of marriage to her daughter arises from it.