Hello Pierre:

You'll be pleased to learn that we have corrected this issue in our upcoming releases 4.3.6 and 04.1-ESV-R15 (due out 7/31/17); and 4.4.0 (release date is TBD).

The issue arises when the client attempts to de-preference a lease. This generally occurs when the server's configuration has changed rendering the lease out-of-range.  The condition was not being accounted for in the client's state machine.  This has been corrected.

We like to thank our contributors by citing them in our release notes. If you would like to be so noted please reply with how you wish to be identified.  Most often it is by name and/or organization.

Thank you for your interest and taking the time to report the issue to us.

Sincerely,

Thomas Markwalder
ISC Software Engineering