I think this report is a duplicate of the issue discussed in #573571, which I haven't been able to reproduce on modern Debian systems. (Debian 9 with insserv 1.14.0 and insserv 1.18.0). As such I think this report can be closed.
If the the bug can be reproduced on Debian 8 or 9, then please let us know or open a new report. - Jesse
