In documentation is specifically said:
It is recommended not to store backup ifcfg files in the same location as the live ones. The script literally does ifcfg-* with an exclude only for these extensions: .old, .orig, .rpmnew, .rpmorig, and .rpmsave. The best way is not to store backup files anywhere within the /etc/ directory.
The /etc/sysconfig/network-scripts/network-functions is using /etc/init.d/functions namely variable __sed_discard_ignored_files:
This caused rhbz#1381314 rhbz#83126 . Please fix initscripts package or documentation.
thanks for the report. Unfortunately it's too late to fix this in RHEL-7.4.
I'm proposing this for RHEL-7.5. I believe you will be able to workaround this yourself in the meantime. ;)
Already fixed in upstream:
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.