Yes the problem is most likely that both sites share the same names in it.
abelt.test is in both setups and even in the root name. Just rename the root to something else more unique would do the trick. It's not something you would see anyway.
"abelt.test" => array( // domain name is used to map to root page
"root" => "abelt", // page name for the root page
"http404" => 1031
),
"alexander-abelt.test" => array( // funktioniert nicht mit /en/ auf Home
"root" => "alexander",
"http404" => 1029
),