When the name in the From address contains a dot, the name should be enclosed in double quotes. Although the code checks a lot of characters that require the quotes ( ()<>:;@\, ), the dot is missing.
The fix is obvious and simple: Just add a dot to the string on line 1267 (version 1.12.1) in Zend/Mail.php.
This issue was ported from the ZF2 Jira Issue Tracker at
Known GitHub users mentioned in the original message or comment:
Fix for Ticket #59
Add test for #59
Fixed with #101