A lot of confusing error messages with ES 5.0.0 and NPM elasticsearch 12.0.1


I am getting a lot of error messages, saying that I cannot bulk update an unexisting index
[2016-11-03T16:41:47,534][WARN ][o.e.a.b.TransportShardBulkAction] [muth_01_dev] unexpected error during the primary phase for action [indices:data/write/bulk[s]], request [BulkShardRequest to [coresystems_core01] containing [41] requests]
org.elasticsearch.index.IndexNotFoundException: no such index)

or that I cannot change a mapping
(error message:
[2016-11-03T16:41:46,686][DEBUG][o.e.a.a.i.m.p.TransportPutMappingAction] [muth_01_dev] failed to put mappings on indices [[[coresystems_core01/z5unTqyiTkeZVx7B-Zh1ZA]]], type [supporters]
java.lang.IllegalArgumentException: object mapping [problemsSolved] can't be changed from non-nested to nested)

When I check my mappings and data, everything seems to be ok.

When I use the older ES 2.4.1 version I do not get those error messages.