Triglavians default to hostile to everyone - you have to actively make them neutral toward you by killing their enemies (Drifters/Sleepers/Rogue Drones in the Pochven region, or EDENCOM forces anywhere - though killing EDENCOM forces will make EDENCOM hostile toward you!)
Slowboating in any ship is always a risk - there are gankers who won’t bother cargo scanning before popping a target they notice slowboating, simply because it is there.
If I am not mistaken there are two types, one will be white and one will be red on your overview. Don’t trust that. I believe both types will attack you by default. CCP has trolled a lot of players hard on that point if I am not mistaken.
As Mkikaden Tiragen says you must actively make them neutral to you, or get used to them shooting at you and anchoring (basically webbing) your ships.
Players also suicide tackle trig victims on gates and let the trigs do the work. Hence for free travel in highsec you need to visit Povchen at least once and shoot a drone.