@MasterPadwan77 you will find info from @RogueZeroRendar to be accurate. The default button for lightsaber activation/deactivation on PS4 is triangle.
Have you changed the default buttons on your game? I'm not sure how this works on PS4 as I play on PC, but the button which triggers saber activation/deactivation is actually tied to the button which activates the lower ability, and not to a specific button. So if your lower ability is changed to another button, so will the lightsaber activation/deactivation.
The lower ability only exists on Galactic Assault when you get the Ion Weapon to make the walkers vulnerable, and on Starfighter Assault as an extra ability which only Poe Dameron and Iden Version have access to.
This is nothing new though. As another example, the dual zoom button is actually tied to the Melee button, so if you change the button to trigger the melee, it WILL also change for the dual zoom. I don't like this design, and EA/DICE failed to acknowledge this anywhere, but it's the way it works.
In PC it's common for people to change these as we have a Key Mapping option, but I don't know how this works on Console
