nisus.com

The first paragraph of the attached document is Times 13, the second is Arial 13. Copy and paste of attributes from the first paragraph to the second does not change the font to Times. But copy and paste attributes from the second to first does change the font.

The Times is Nisus "internal default" (along with black colour and 12pt, I think). Nisus seems to treat these things as "not applied" so they don't carry over (or in other words, if you apply them Nisus seems to remove them!). I'm not really that sure about all the interactions with default settings (in Preferences, Normal style, etc.)

Philip has the right of it: copy-pasting attributes will only duplicate explicitly defined attributes. Your first paragraph is in the Times font only because that's the default it assumes from your document's Normal paragraph style. This happens even though Normal isn't explicitly applied to the first paragraph; after all, some font must be used for the text.

I hope that makes some sense.