Weirdest Problem Yet: Melodyne and X1 Ruining a Project

1-Tediously corrected 2 lead vocal and 8 vocal harmony tracks using Melodyne.
2-As advised here, I started bouncing them one by one, planning to save the source project file, but then create a copy with only the bounced tracks.  This is because I was having trouble with Melodyne getting out of sync and also crashing my system.
3-Bounced lead tracks are OK as are harmonies 1 and 2.
4-On harmonies 3 and 4, the bounced tracks have the correct material PLUS a weird echo of either harmony 1 or 2 (they are the same part double so I am not sure which one it is).
5-Now the mind-blowing part: when I go back to the source tracks for harmonies 3 and 4 (the original tracks that have Melodyne FX), I can hear the weird echo whether Melodyne is of or on BUT when I click just in the Melodyne window and play the transferred and edited  material, I do NOT hear the weird echo.
 
To summarize, I suddenly have extraneous audio in the bounced track, in the source track with or without Meldyne, but NOT in Meldoyne alone.
 
How is this possible?
 
Note that I have checked all inputs, outputs, and sends, and have no effects (other than Melodyne).  WTF??