pkg-1.14.7 miscalculates needed disk space

[yurivict]

pkg installed 242 packages

Number of packages to be installed: 242

The process will require 3 GiB more space.

and ended up with negative Avail number:

Filesystem         512-blocks      Used    Avail Capacity  Mounted on
/dev/gpt/ssdrootfs  340579192 315734800 -2401936   101%    /

It should take into account both installed files size, and size of downloaded packages in /var/cache/pkg (in case /var/cache/pkg is mounted on the same disk as /usr/local as it is in my case). Apparently, it makes a mistake somewhere.