LBL_NO_SUBJECT in Email.php

Just installed SuiteCRM 7.9.8. with no visible error or warrning but apache2/error log show series of errors:
[color=#0000bb]PHP Notice: Undefined index: LBL_NO_SUBJECT in …/modules/Emails/Email.php on line 3085[/color]

Outgoing Email is configured (gmail) and works just fine.

Have anyone experienced this issue ?

Installation output:

System Environment
PHP Version7.0.22-0ubuntu0.16.04.1
XML ParsingOK
MB Strings ModuleOK
Writable SuiteCRM Configuration File (config.php)OK
Writeable Custom DirectoryOK
Writable Modules Sub-Directories and FilesOKWritable Upload Directory OK
Writable Data Sub-DirectoriesOK
Writable Cache Sub-DirectoriesOK
PHP Memory LimitOK (256M)
ZLIB Compression ModuleOK
ZIP Handling ModuleOK
PCRE LibraryOK
cURL ModuleOK
Upload File SizeOK
Sprite SupportOK
PHP allows to use stream (upload://)OK
Location of your PHP configuration file (php.ini):/etc/php/7.0/apache2/php.ini