Operation DoMonthlyReportOperation failed : Illegal semicolon, not in group

Hi,
Since update 1.8.15, I receive some errors from ZxAdmin.

This is an automated notification from ZxAdmin about DoMonthlyReportOperation.

Operation DoMonthlyReportOperation failed.

Operation Id: 706377ef-160d-4628-ade6-ac56d9c00719
Operation Host: *

Scheduled operation

ZeXtras Version: 1.8.15
ZeXtras commit: ab503ce42960515b0c733578697c3907ab7d6601
Zimbra version: 8.0.7_GA_6021 20140408123908 20140408-1242 FOSS

- exception -
Illegal semicolon, not in group

I also changed "Notification e-mail recipient(s)" and "Additional License Warning Emails" in Core tab. These values have now one email address ( 2 before) and end with semicolon (can't delete it). Maybe it's not important but i don't want to miss something.

Anyone has this error ?