#1. When copying kerning classes from one font to another using copy paste, the kerning will appear in the kerning window but the data won’t apply to the targeted font.
#2. On remove the kern data braces remain (like remnants) until file reopens.
Is this a bug?
Did you copy kerning or kerning groups?
Both, or what ever is displayed in the kerning window?
The kerning window shows only the kerning. The classes are in the glyphs. You can import them from File menu > import > Metrics. Select all glyphs in the font view before you import.