Related Select-field behaving weirdly when ->searchable() is added

Hi! I'm filling a Select form-field, with related content. (Sender -belongsTo- Message) It works as expected, but when I add ->searchable() to the field, the searchresults only returns a '1'. What can be the problem? Is searchable not to be combined with a relation-field? This may of may be not related to: https://discord.com/channels/883083792112300104/1081251549944238131