NRF.setServices .. onWrite called twice

Hi,

there is NRF.setServices and I have no trouble setting up a custom service and characteristics when executing code in the IDE, and use it thereafter. Then I tried to put this in a .boot.js file and an issue pops up: the writable characteristic calls onWrite twice each time a message arrives.

So I thought its because setServices is called multiple times (e.g. after long-press BTN3), but even the following doesn't solve it:

setTimeout(() => {
  var cc = require('concom');

  cc.t = (0|cc.t) + 1;

  function has_service(sid, cid) {
    var svc = {};
    svc[cid] = {};
    var svcs = {};
    svcs[sid] = svc;
    try {
      NRF.updateServices(svcs);
    } catch (e) {
      return false;
    }
    return true;
  }

  if (has_service(0xf011, 0xf012)) return;

  NRF.setServices({
    0xf011: {
      0xf012: {
        maxLen: 53,
        writable: true,
        onWrite: (e) => cc.read(new Uint8Array(e.data))
      },
      0xf013: {
        maxLen: 53,
        notify: true
      }
    }
  });
}, 3 * 1000);

When I run its parts individually, everything works (e.g. first has_service returns false, then setServices, then has_service returns true) and I get one onWrite per message. When I do a hard reset with this in the boot file and write to the characteristic, onWrite gets called twice.

It would be great if anyone could shed some light on this :)

edit: .t is 1