Flatlining on back of quilt intermittently

[Donna TKO]

Hello!  I'm a newbie and am seeing the same "flatlining" issue.  It's short little bursts of flatlining, and I didn't notice until I took the quilt off the machine.  I'm so thankful for all this information, I plan to use all of it until my problem is fixed.  

The question I have though, is this:  What about this quilt I just finished?  Is it ruined, will the back stitching fall out the first time I wash it? I kind of planned to give it as a gift, I'm sure the person receiving the quilt won't notice, but I'm afraid it will pull apart when it's washed and I'll look like a fool...I am examining it too closely?

Thanks!