15weeks - heard heartbeat in 2 places..

PC • Mama to Cruz 💙 Kaia 💖 and Shaea to come 💗
..and no, one is not mine. They're both very fast - one is a lot louder on the left and one is less loud but just as strong on the right, and there's no noise in the center. 
My last sono was at 9 weeks and clearly showed one babe but tonight freaked me out! I've researched and some say it can Echo or be the placenta giving off the same beat, so I'm a bit less crazed - still. So crazy! Has this happened to anyone else? 

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