_area._area-blocksize incorrect for BI

OE 11.6.0

AIX 7.1.0.0

Client has two production databases, both have BI block size of 16 KB. Each BI is a single variable extent.  According to (4234), DBs were created under 11.3.2 prostrct create, not upgraded via conv1011 (in case that matters).

There are various ways to determine the BI block size:

• (4251) message in db log
• proutil describe
• _area-blocksize (area 3)
• _logging-biblksize
• _dbstatus-biblksize
• (_filelist-size * 1024) / _areastatus-totblocks (for the BI extent record; _filelist-id = 2 in this case)

These should all agree.  For one of the DBs, they all equal 16384.  For the other, they all agree that the BI block size is 16384, except that _area._area-blocksize (where _area-number = 3) is 8192.

I checked the KB but can't find a bug for this.  Has anyone found _area._area-blocksize to be unreliable?