ESA CHANGES IN SOCIAL SECURITY BENEFITS LETTER

Two days ago I received a letter from the DWP about the upcoming changes in ESA rates from April this year. It informed me that from 10th April 2023 the rates of Social Security Benefits will change and my ESA will be £225.45 a week
This is because of ... a change in the rates of Social Security benefits.
It went on to state
From 26th December 2023 your ESA will be £129.50 a week
This is because of ... an age change

I reach 66 on 27th December.

But this is where I am confused. It can't be an actual pension forecast because I checked on the Government Gateway and according to that I should be entitled to the full new state pension at my retirement. And surely it cannot be ESA because, unless I have it wrong, ESA finishes when you reach state pension age.

Any idea what on earth they are on about???

I got my change in benefits letter, thought it was going up by 10%. Mine went from £129.50 a week to 129.65 a week. A whole 15p. Don’t quite know where I’ll spend this extra but 60p every 4 weeks , won’t buy a bottle of milk