I remember people who said kufr things a while back and I warned them but now I am questioning if it is mandatory for me to say if they were a kafir back then but a Muslim now since I warned them.They changed now and I’m thinking that since it was the past I should ignore it and only worry about now

Ustadh AbdulAziz al-Haqqan

Stop fueling your waswas and never ask these questions again to feel better from the waswas.