This correction discusses the front neckline gaping. It can happen for various reasons like the bust need more shaping or the neck widths not matching.
Tilly and the Buttons: Five Ways to Fix a Gaping Neckline
Adjusting a Gaping Neckline
Fix Front Neck Gaping – Option 1 - with Princess Seams from the Armhole - How to correct a neckline
Tutorial: how to fix a gaping neckline
Fixing Front Neck Gaping – Option 2 - with Princess Seams from the Shoulder - Fix a neckline pattern
Fixing a Neckline that is too big & gapes : 10 Solutions - SewGuide
How To Fix A Gaping Neckline
The Fitting Book E Book 19-11-2021, PDF, Seam (Sewing)
How to Fix a Gaping Neckline
6 Ways to Fix a Gaping Neckline
6 Ways to Fix a Gaping Neckline
Tutorial: how to fix a gaping neckline
fitting and pattern correction for back neckline gaping – In-House Patterns
How to Adjust for Neckline Balance