I just passed 100,000 on my 2018 and got the same warning. Nothing in the manual, dealer had no idea but when I took it in said it’s an interference engine with recommended timing Chain replacement at 100,000mi. Transmission has to come out to even see if the chain looks worn. 16hrs of labor… $4400 ? I haven’t done it. So disappointing! I really like the car but it’s not worth having to do this every 4 years. Now I’m trying to decide if I trade it or not.