Generalized relation_member tables are loosing records during update

[zdila]

generalized_tables:
  route_members_gen1:
    source: route_members
    tolerance: 50
tables:
  route_members:
    type: relation_member
      relation_types:
        - route
      mapping:
        route:
          - hiking
      columns:
        - name: osm_id
          type: id
        - name: member
          type: member_id
        - name: geometry
          type: geometry
        - name: role
          type: member_role
          key: role
        - name: type
          type: member_type

On initial import the table route_members_gen1 is correctly populated but during longer period of applying minutely updates the records from route_members_gen1 starts to disappear - all members of a (modified?) route at once.