Formatter produces garbage

When formatting the following code, the Xtend formatter produces garbage:

package com.btc.serviceidl.generator.cpp

import java.util.Collection
import org.eclipse.emf.ecore.EObject

class CodecGenerator 
{    
    Object typeResolver
    
    def generateHeaderFileBody(EObject owner)
    {
        var Collection<EObject> nested_types
        '''
               «FOR type : nested_types»
                   «/* TODO */»
                   «val proto_type_name = typeResolver.toString»
               «ENDFOR»
        '''
    }
    
}

The result is:

package com.btc.serviceidl.generator.cpp

import java.util.Collection
import org.eclipse.emf.ecore.EObject

class CodecGenerator
{
    Object typeResolver

    def generateHeaderFileBody(EObject owner)
    {
        var Collection<EObject> nested_types
        '''
            «FOR type : nested_types»
                «/* TODO */»
                   «val proto_type    e = typeResolver.toString»
            «ENDFOR»
        '''
    }

}

Parts of the name of the proto_type_name variable are replaced by spaces here, and the indentation is also not correct. The comment in the line before seems to confuse the formatter.