This occured to me when reviewing the Kobold Sorcerer Grimmnir from the "Little Trouble in Big Absalom" Module.
As a Sorcerer of the demonic bloodline, Grimmnir is a spontaneous divine spellcaster. As indicated on p.191 Core Rulebook (2nd printing) he has these proficiencies regarding his spellcasting:
Trained in spell attack rolls of your spellcasting tradition, as indicated by your bloodline. Trained in spell DCs of your spellcasting tradition, as indicated by your bloodline
That gives Grimmnir a trained (+3) bonus to his Spell Attack Roll, as well as his key ability modifier CHA (+4), resulting in a +7. This is also indicated on his pregen character sheet.
Ranged [two-actions] acid splash +7 (cantrip), Damage 1d6 acid plus 1 splash
But when I looked up the Acid Splash Entry (p. 316 Core Rulebook (2nd printing)), it says Acid Splash is a cantrip of the arcane and primal tradition.
- does he actually get only a +4 (key ability modifier 4 + untrained tradition 0) ?
- is he automatically trained in cantrips he earned from your bloodline
- are cantrips he earned from his bloodline automatically considered of the tradition he gained from his bloodline?
- does his spell attack work for for every spell he has, regardless of tradition?
1: would be... bad design for this bloodline? 2: you usually don't use proficiency with a single spell. 3+4: would have the same outcome here, but could work differently if there are classes that actually gain proficiency in more than one tradition.