Debug World duplicated blocks

Short description :

In the debug world, I noticed that the last block of each row is an exact duplicate ( exact same state ) of the first block of the following row.

Steps to reproduce :

Open the debug world, look at the last block of a row and the first block of the next row

Expected result :

There should be only one block of each state ( As in 1.21 )

Actual result :

There is 2 blocks with the same state for each row ( in 26.1 and 26.2 )

Is it a feature to better track block state lines after lines or is it a bug ?