Bug 403681

SUMMARY
Sending out mail by using distribution lists may lead to an incorrect mail delivery. The problem occurs if two or more distribution list names start with the same string, followed by a SPACE, followed by a unique identifier.

Example:

Name for distribution list 1: GRP A
Name for distribution list 2: GRP B

Each distribution list contains at least one valid email address which differs.

STEPS TO REPRODUCE
1. Create 2 distribution lists named "GRP A" and "GRP B" (without quotes, there is a blank between GRP and the group identifier A/B).
2. Add one email address to "GRP A" and a different email address to "GRP B".
3. Create and send out two emails. The first should be addressed to "GRP A" and the second to "GRP B".

OBSERVED RESULT
As a result you should see 2 emails which have been sent to the recipients contained in "GRP B". The recipients in "GRP A" will never receive the email.

EXPECTED RESULT
The members of "GRP A" and "GRP B" should get the email which has been addressed to them.

SOFTWARE/OS VERSIONS
Windows: 
MacOS: 
Linux/KDE Plasma: openSUSE Tumbleweed 20190125
(available in About System)
KDE Plasma Version: 5.14.5
KDE Frameworks Version: 5.54.0
Qt Version: 5.12.0

ADDITIONAL INFORMATION
Replacing the SPACE with a "-" will lead to a correct delivery.
Replacing the SPACE with a "_" will lead to a message that says the email address isn't correct because the address contains no "."