Hello There!
I am not 100% sure but I think i know what kind of problem you are facing. I also had this problem on my blog TheTechSecrets.CoM. I report them(colorlib) about this problem like you, but they could not fix. But some how I fixed the problem by myself now my all tag links are working properly. You can check my ques which i asked to them.
Problems With Tags- TheTechSecrets
Now how i fixed the problem is, I just deleted the post which was coming in every tag link. Yup! Thats it… It fixed my problem.
You can also check if this problem gets resolved by editing the the post’s URL or you have to delete that post like me.
TheTechSecrets Team!