I read Three Books On Padre Pio. He did not like Jehovah Witnesses. I do not mean hate but disliked.
After World War Two the Jehovah Witnesses came to Italy. He did not mind meeting Protestants. He meet his first protestants during the war and after from American soldiers who would visit. He was asked why he did not convert the Protestants. He declared "If God wants them Catholic he will do it."
I really believe he would do this because he could see into the spiritual realm. Traditional Protestants believe in 1John 4. So he could see the Holy Spirit in a person. Jehovah Witnesses do not believe Christ came in the flesh as Divinity like it declares in the bible. This is very important as St. John declares in his epistle.
Padre Pio "flipped his wig" when he heard the were going door to door in his home town. He appeared in his home town.