Incomplete pkg_summary

[Jason Bacon <outpaddling%yahoo.com@localhost>]

My 2018Q2 bulk build on CentOS 7 is missing a lot of packages from 
pkg_summary, even though they were built successfully.  Among the 
missing are virtually all python packages.

File counts:

www/pkgsrc/packages/sharedapps/pkg-2018Q1/Darwin16/All    15445
www/pkgsrc/packages/sharedapps/pkg-2018Q1/Darwin17/All    15441
www/pkgsrc/packages/sharedapps/pkg-2018Q1/NetBSD-7.1.1/All    16202
www/pkgsrc/packages/sharedapps/pkg-2018Q1/RHEL6/All    17303
www/pkgsrc/packages/sharedapps/pkg-2018Q1/RHEL7/All    17552
www/pkgsrc/packages/sharedapps/pkg-2018Q2/Darwin17/All    15428
www/pkgsrc/packages/sharedapps/pkg-2018Q2/NetBSD-7.1.1/All    19300
www/pkgsrc/packages/sharedapps/pkg-2018Q2/RHEL6/All    17645
www/pkgsrc/packages/sharedapps/pkg-2018Q2/RHEL7/All    17781

zcat pkg-2018Q1/RHEL7/All/pkg_summary.gz |wc
  543577 1389600 19468053

zcat pkg-2018Q2/RHEL7/All/pkg_summary.gz | wc
  190149  493622 7208237

zcat pkg-2018Q1/RHEL7/All/pkg_summary.gz | grep 'FILE_NAME.*py36' | wc
     833     833   29465

zcat pkg-2018Q2/RHEL7/All/pkg_summary.gz | grep 'FILE_NAME.*py36' | wc
       0       0       0

zcat pkg-2018Q1/RHEL7/All/pkg_summary.gz | grep 'FILE_NAME.*py27' | wc
    1151    1151   42358

zcat pkg-2018Q2/RHEL7/All/pkg_summary.gz | grep 'FILE_NAME.*py27' | wc
       1       1      40

Anyone seen this before?  Suggestions on how to diagnose/fix it?

The build was interrupted by a power outage, but so were all the other 
builds and they're not exhibiting any problems.  E.g. CentOS 6:

zcat pkg-2018Q2/RHEL6/All/pkg_summary.gz | wc
  540643 1391071 19296001

zcat pkg-2018Q2/RHEL6/All/pkg_summary.gz | grep 'FILE_NAME.*py27' | wc
    1171    1171   43016

Thanks,

    JB