Rumple was kind of distracted with trying to get Belle back. Bae even said to him something along the lines of “You’ve spent years looking for me then I come to town and you just disappear”. Perhaps Rumple didn’t think Storybrooke was in much danger until GOAT started drawing attention to themselves. Greg was sneaking around Storybrooke unnoticed by everybody whilst Tamara was pretending to be Neal’s beloved fiancée. Rumple didn’t bother meeting Tamara, perhaps if he had, he may have sensed that she wasn’t what she seemed.