Unhandled Exception ("TypeError")

Today I rebased to the latest stable branch and I get a exception message (see title) when I attempt to look at collapsed (older) comments of a differential revision.

Reproduction Instructions

  • update stable branch

  • view a differential revision with old comments

  • click “Show older changes”

  • see popup:
    Unhandled Exception (“TypeError”)

    Argument 1 passed to DifferentialTransactionView::setLeftDiff() must be an instance of DifferentialDiff, null given, called in /var/www/phabricator/phabricator/src/applications/differential/engine/DifferentialRevisionTimelineEngine.php on line 74
    

Phabricator/Arcanist Version
phabricator
56113632ddc7701993d1c1adc49a017f3a304772 (Wed, Nov 27) (branched from eb6df7a2091a9477523c97b485277ab68af61a0a on origin)
arcanist
bac2028421a4be6e34e08764bbbda49e68b3a604 (Tue, Nov 19) (branched from cc850163f30c4697e925df0d6212469679600a2c on origin)
phutil
1750586fdc50a6cd98adba4aa2f5a7649bd91dbe (Sep 30 2019) (branched from 39ed96cd818aae761ec92613a9ba0800824d0ab0 on origin)
php
7.3.11-1+0~20191026.48+debian10~1.gbpf71ca0
diff
3.7 at /usr/bin/diff
git
2.20.1 at /usr/bin/git
hg
Not Available
pygmentize
2.3.1 at /usr/bin/pygmentize
svn
1.10.4 at /usr/bin/svn