see dev comment here:

• "A lot of people are still running old nodes, still making it hard to reach consensus. On my wallet, only 37% (10/24) of the NN-capable connections are running 3.5.9.2."

The 3.5.9.1 version was a fix for the "causes" of the 148h-long superblock (see dev review),
and the 3.5.9.2 is a fix of the 3.5.9.1 (some people had only 7 or 8 whitelisted projects in the SB, not 25 as usual)

And once many run the 3.5.9.2 version we will find out if the bug is fixed or something is still missing...