Kevin Costner and Josh Lucas, both portraying John Dutton on Yellowstone, were intentionally kept apart on set to preserve the character's essence without Lucas mimicking Costner, as directed by creator Taylor Sheridan. (148 characters)
They stayed separate deliberately to avoid Lucas doing a Costner impression and to capture the character's core spirit across ages.
"Luckily, he’s not there when I’m shooting.... That’s what we talked about." – Josh Lucas in 2021 Collider interview
"These men don’t necessarily need to look alike. They need to have the essence of each other." – Josh Lucas to Deadline
No bad blood existed; the choice was practical for maintaining character integrity.