welcome home mimi!
Battleaxe curves in strips mean the feed dogs are doing the job too well, they need a hand from you
Make sure each strip is same as the others. Or that the border is the same length.
You can pin if you want. Because I already know they will come out right I use my right hand to pinch the strips together as they go through the machine. When that bit gets through I stop, pick up the strip about 12-18" back and do the same again.
Like making 9 patches to check accuracy, you can take a couple of equal scrap strips, sew them without any guidance, then sew another set minding that feed dog pull. You will see the difference
LIfe is good, proceed with vigor ~