KB482855: Layout names are incomplete if the option "Sheet break between groups" checked when a document is exported to Excel

SYMPTOM:
When a document with multiple layouts is exported to Excel, the sheets of Excel are automatically named as layout names by expectations. While if the layout contains a Grouping attribute and "sheet break between groups" option checked when exported, the layout name doesn't display completely.
STEPS TO REPRODUCE:

• Create a document.
• Name layouts with 31-character-length name.

• Add Category in Grouping field, and check option “sheet break between groups”. 
• Export the document to excel. The second layout name is truncated in Excel, as showed below.

CAUSE:
This issue is caused by the limitation of excel as well as the number of Group-Bys.
ACTION:
If there are many Group-Bys in one layout, avoid naming layout in a too long name.
Below article provide another scenario about not showing complete  layout name in Excel:
KB482912: Layout name longer than 31 characters would not fully show as sheet name when exporting to Excel