I encountered the Pulsos minor civ, did praise action twice to boost them to +5 relationship per turn (from natural +1).

In Autosave 192 (turn 41) you can see Pulsos are at 10 relations, +5 per turn, with 8 turns of praise remaining.

In Autosave 193 (turn 42), if you select the Pulsos very quickly after loading, you see relations at +5 per turn as expected.  But a few seconds later, the minor faction screen closes on its own, and if you open it again it is down to +1 per turn, with the praise effect erased.

Possibly related:  A different minor faction is assimilated by an AI player on that turn.

AutoSave 193.savAutoSave 192.sav

Chosen hacking action by AI on minor faction could be explaining this result - at least I'd guess.

I haven't purchased any expansions, so unless I'm much mistaken, hacking is not available.

(Plus, I doubt that would explain the minor faction info screen closing on its own.)