Knitting Dropped Stitches

I’m knitting a sweater with size 12 needles. It is knitted in the round until the start of the sleeves. A pattern is worked using dropped stitches. Round 1: Purl stitches.  Round 2: Dropped stitches with 3 yarn overs, 1 knit stitch. Round 3: Purl stitches, let the yarn overs drop.
My problem is that on Round 3, the yarn-over stitches pull together so tightly that I can’t slide them from the middle part of the circular needle onto the knitting needle.
HELP—what am I doing wrong?

Best regards 

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