My muscles are not sore


I've been doing FitnessBlender workouts for a few years now and after every workout complete my body would be really sore but recently I've had the chance to use heavier weights (before i was using 5 kg maximum and now I use from 6 to 26 kg for my legs) and while doing the workout feels like i'm really working my muscles, I don't feel that sore the next day, I barely feel it. Is this normal or i'm doing something wrong? I check my form every time and i feel that i'm doing it right, especially as I've been doing these workout moves for years... Has anyone else experienced this?