Natural -10 Relations Mechanic Question

[NachoToast]

Does the natural tendency for some factions to -10 relations every once in a while stay in effect if the faction is in an allied relation?

[Canute]

The natural tendency indicate, when you have no interaction with that faction it will slowly move toward that value.
Even allied relation will decay.

Just ask yourself, what happen to your "best" friend when you don't contact/visit him for years ?

[NachoToast]

Oh, that makes sense, thanks for the help!