Warnings below, this is trying to install on 2.5.
I've also manually cleared silverstripe-cache to no avail.
Warning: There are two files both containing the same class: '../cms/code/CommentAdmin.php' and '../comments/code/CommentAdmin.php'. This might mean that the wrong code is being used. in ..\sapphire\core\ManifestBuilder.php on line 487
Warning: There are two files both containing the same class: '../cms/code/sitefeatures/SSAkismet.php' and '../comments/code/SSAkismet.php'. This might mean that the wrong code is being used. in ..\sapphire\core\ManifestBuilder.php on line 487
Warning: There are two files both containing the same class: '../cms/code/CommentTableField.php' and '../comments/code/formfields/CommentTableField.php'. This might mean that the wrong code is being used. in ..\sapphire\core\ManifestBuilder.php on line 487
Warning: There are two files both containing the same class: '../cms/code/CommentTableField.php' and '../comments/code/formfields/CommentTableField.php'. This might mean that the wrong code is being used. in ..\sapphire\core\ManifestBuilder.php on line 487
Warning: There are two files both containing the same class: '../cms/code/sitefeatures/Akismet.php' and '../comments/code/thirdparty/Akismet.php'. This might mean that the wrong code is being used. in ..\sapphire\core\ManifestBuilder.php on line 487
Warning: There are two files both containing the same class: '../cms/code/sitefeatures/Akismet.php' and '../comments/code/thirdparty/Akismet.php'. This might mean that the wrong code is being used. in ..\sapphire\core\ManifestBuilder.php on line 487