[ubuntu] etckeeper not commiting after apt

I've been using etckeeper for about 5 years to keep track of changes I make to config files (and to detect strange changes). I first used mercurial and, in the last year, I started using git for new installations.

I always make the following changes in order to see if I (or someone/thing else) changed anything since I last commited or installed something:

AVOID_DAILY_AUTOCOMMITS=1

AVOID_COMMIT_BEFORE_INSTALL=1

However, yesterday I installed etckeeper with git on my first 16.04 (a system76 lemur notebook) and it seems that it is NOT commiting AFTER it runs APT, as it always did.

Anyone can think what may be wrong?

TIA