Quick fix: If you're still on the same row, unknit back to the wrong turn. Re-turn the work, bring the yarn to the front, slip the first stitch purlwise, then pull both legs of the stitch up over the needle tip to create the correct double stitch (DS).
What you are seeing
Your German short row (GSR) has a hole, a gap, or a visible bump where it shouldn't be. The double stitch (DS) — the two-legged stitch created at the turn — is either missing, in the wrong place, or wasn't worked correctly when you came back to it.
Why it happens
- Forgetting to pull the yarn up to create the double stitch after turning
- Working the double stitch as two separate stitches instead of together as one
- Turning in the wrong place — one stitch too early or too late
- Confusion between RS and WS turns (the yarn direction differs)
Fix it now
- Identify exactly what went wrong: is the double stitch missing, in the wrong position, or worked as two stitches instead of one?
- If worked as two stitches: when you encounter it on the return row, you'll have an extra stitch. Work the two legs together as k2tog or p2tog to close the gap.
- If the double stitch is missing entirely: a hole will form. Drop down to the turn row and re-create the turn correctly using a crochet hook, then re-knit up.
- If you turned in the wrong place: unknit back to the correct turn position and work the turn again.
Prevent it next time
- When you turn, immediately say: "yarn forward, slip 1, pull both legs up" — the three-step sequence for a DS
- Mark each short row turn point with a locking stitch marker so you can identify DS stitches easily
- On the return row, look for the distinctive two-legged stitch and work both legs together