couchdb修订号跳转和文档更改导致冲突

I'm encountering a weird problem with couchDB. Some documents in my database can't be updated due to unknown conflicts. When comparing them to other documents in Futon I don't see any big differences to other documents. When I try to update one of those documents the revision number jumps from e.g. 45 to 58 but no changes are visible. This is what I see in the couchdb log file..

[Tue, 22 Nov 2016 13:45:10 GMT] [debug] [<0.30579.229>] Minor error in HTTP request: conflict
[Tue, 22 Nov 2016 13:45:10 GMT] [debug] [<0.30579.229>] Stacktrace: [{couch_db,update_doc,4,
                                  [{file,"couch_db.erl"},{line,432}]},
                                 {couch_httpd_db,update_doc,6,
                                  [{file,"couch_httpd_db.erl"},
                                   {line,753}]},
                                 {couch_httpd_db,do_db_req,2,
                                  [{file,"couch_httpd_db.erl"},
                                   {line,234}]},
                                 {couch_httpd,handle_request_int,5,
                                  [{file,"couch_httpd.erl"},{line,318}]},
                                 {mochiweb_http,headers,5,
                                  [{file,"mochiweb_http.erl"},{line,94}]},
                                 {proc_lib,init_p_do_apply,3,
                                  [{file,"proc_lib.erl"},{line,239}]}]
[Tue, 22 Nov 2016 13:45:10 GMT] [info] [<0.30579.229>] 127.0.0.1 - - PUT /DBNAME/external_link-35174841-41a5-44e3-a567-ec56209dc8b8-de_DE-1 409
[Tue, 22 Nov 2016 13:45:10 GMT] [debug] [<0.30579.229>] httpd 409 error response:
{"error":"conflict","reason":"Document update conflict."}

Any ideas what's going on here?

The docs say that conflicts can occur when several threads or programs try to update a document at the same time.

Are you sure you don't have another thread writing in your database, maybe a mapreduce? That would explain the different revision numbers.