TIK2024

I used to have 11 years national insurance contributions on my record. It has now been reduced to 9?? I've been on DLA and then PIP for many years. I remember DLA used to give NI credits at one point before moving to PIP. Is this correct? I wonder if this is what has made the record change and that the years I was on DLA and given NI credits (as was allowed then) have now for some reason been removed. Can someone please advise if I'm wrong and credits were NEVER given to people on DLA before? Thank you so much.