Vuejs with axios request in vuex store: can't make more than one request, why?

I'm building some vuejs dashboard with vuex and axios, between others, and I've been struggling for a while on a pretty pesky problem: it seems I can't make more than one request! All subsequent calls fail with this error:

Fetching error... SyntaxError: Failed to execute 'setRequestHeader' on 'XMLHttpRequest': 'Bearer {the_entire_content_of_the_previous_api_response}' is not a valid HTTP header field value.

My store looks like that:

import axios from "axios";

const state = {
  rawData1: null,
  rawData2: null
};

const actions = {
  FETCH_DATA1: ({ commit }) =>
  {
    if (!state.rawData1)
      return axios.get("/api/data1")
      .then((response) =>
      {
        commit("SET_RAW_DATA1", response.data);
      });
  },

  FETCH_DATA2: ({ commit }) =>
  {
    if (!state.rawData2)
      return axios.get("/api/data2")
      .then((response) =>
      {
        commit("SET_RAW_DATA2", response.data);
      });
  }
};

const mutations = {
  SET_RAW_DATA1: (state, data) =>
  {
    state.rawData1 = data;
  },

  SET_RAW_DATA2: (state, data) =>
  {
    state.rawData2 = data;
  }
};

export default
{
  namespaced: true,
  state,
  actions,
  mutations
};

I don't think my API has any problem, as everything seems to work smoothly via Postman.

Maybe it's obvious for some, but I can't spot what's the matter as I'm still quite a vue noob...

Oh, and I'm handling the axios Promise like this, if this is of any interest:

this.$store.dispatch("api/FETCH_DATA1").then(() =>
{
  // parsing this.$store.state.api.rawData1 with babyparse
}).catch((err) =>
{
  this.errorMsg = "Fetching error... " + err;
});

After @wajisan answer, it does seem to work with "traditional" calls, but not with fetching file calls. I've tried stuff with my Echo api, to no avail... More details there: Serving files with Echo (Golang).

Any ideas, pretty please? :)