In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/etc/uci-defaults/13_fix_group_user line 3:

. /lib/functions.sh

  ^---------------^ SC1091 (info): Not following: /lib/functions.sh was not specified as input (see shellcheck -x).

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/etc/uci-defaults/13_fix_group_user line 5:

for file in `grep -sl Require-User /usr/lib/opkg/info/*.control`; do

            ^-- SC2013 (info): To read lines rather than words, pipe/redirect to a 'while read' loop.

            ^-- SC2006 (style): Use $(...) notation instead of legacy backticks `...`.

Did you mean: 

for file in $(grep -sl Require-User /usr/lib/opkg/info/*.control); do

For more information:

  https://www.shellcheck.net/wiki/SC1091 -- Not following: /lib/functions.sh ...

  https://www.shellcheck.net/wiki/SC2013 -- To read lines rather than words, ...

  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...