Hi,

I don't know if this is rather a general elasticsearch issue but I found this "bug" in the apm-server Index template.

The dynamic_templates section in the exported Index Template contains objects with the same key which leads to overwrites rather than appends in the final Index Mapping.

The apm-server Index template contains the following definitions when exported with the apm-server export template command. Used version here is 6.8.2

        {
          "context.tags": {
            "mapping": {
              "type": "keyword"
            },
            "match_mapping_type": "string",
            "path_match": "context.tags.*"
          }
        },
        {
          "context.tags": {
            "mapping": {
              "type": "boolean"
            },
            "match_mapping_type": "boolean",
            "path_match": "context.tags.*"
          }
        },
        {
          "context.tags": {
            "mapping": {
              "scaling_factor": 1000000,
              "type": "scaled_float"
            },
            "match_mapping_type": "*",
            "path_match": "context.tags.*"
          }
        },

Those three definitions share the same "context.tags" key
When deployed and a Index is created with this template, only the last "context.tags" definition is contained in the Index Mapping, which leads to indexing failures when the field value is not a float

Renaming the keys to unique values as a workaround seems to fix this.

In the 7.x Index Template context.tags is replaced by labels which seems to have the same issue (not tested)