[Edi]

The first one of those is a bug.

Border mountains not counting as mountains for terrain purposes of spells is not a bug as such, but is either a bug or a feature, depending on point of view. They tend to count as mountains for the purposes of sites and resources and as plains in all other regards (e.g. what forts you can build etc). In any case, change to border mountain mechanics are very unlikely.

Forest of Joy is supposed to be an air site. The Ashen Forest is a death site, Dragon Forest is fire and Cypress Woods iirc was also an air site. Site name does not need to determine its magic affiliation at all.