The tribe wasn’t an uncontacted tribe.

The Matsés had developed many survival techniques to avoid being detected by settlers, such as teaching their dogs not to bark when ordered, cultivating small farms in different hidden parts of the forest, and establishing shorter periods of itinerant agriculture

Nothing about women being kidnapped.

It mentions the ambush, it just doesn’t specify the details.

In October 1964 in Requena province, in the east of Loreto, Peruvian lumberjacks and colonists were ambushed by a group of Matsés.

From another source, Jagua: A Journey Into Body Art From The Amazon