Migrating to Meteor 1.7.0.4 : MongoDB : "updating the path ... would create a conflict at ..."

Im using meteor, and im trying to go from meteor 1.6 to 1.7 But im encountering errors im unable to get informations about in my tests :

tests.jpg

I get multiple things like this (some are maybe redondant, unused or obsolete) :

Error: Updating the path 'relationChangeRate' would create a conflict at 'relationChangeRate'
at Function.MongoError.create (C:\Users\fquesselaire\AppData\Local\.meteor\packages\npm-mongo\3.0.11\npm\node_modules\mongodb-core\lib\error.js:45:10)
at toError (C:\Users\fquesselaire\AppData\Local\.meteor\packages\npm-mongo\3.0.11\npm\node_modules\mongodb\lib\utils.js:149:22)
at C:\Users\fquesselaire\AppData\Local\.meteor\packages\npm-mongo\3.0.11\npm\node_modules\mongodb\lib\collection.js:1029:39
at C:\Users\fquesselaire\AppData\Local\.meteor\packages\npm-mongo\3.0.11\npm\node_modules\mongodb-core\lib\connection\pool.js:544:18
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickDomainCallback (internal/process/next_tick.js:218:9)

not occurring in 1.6.*

I tried upgrade my mongodb to 3.6.6, no effect. Im also unable to get the entire stack in tests to see what is exactly enforcing.

my .meteor/versions :

255kb:meteor-status@1.5.0
accounts-base@1.4.2
accounts-password@1.5.1
akasha:fs-extra@0.26.3
alanning:roles@1.2.16
aldeed:autoform@6.3.0
aldeed:autoform-bs-button-group-input@2.0.0
aldeed:autoform-select2@3.0.1
aldeed:collection2-core@2.1.2
aldeed:template-extension@4.1.0
allow-deny@1.1.0
arillo:flow-router-helpers@0.5.2
autoupdate@1.4.1
babel-compiler@7.1.1
babel-runtime@1.2.4
base64@1.0.11
binary-heap@1.0.10
blaze@2.3.2
blaze-html-templates@1.1.2
blaze-tools@1.0.10
boilerplate-generator@1.5.0
caching-compiler@1.1.12
caching-html-compiler@1.1.3
callback-hook@1.1.0
check@1.3.1
coffeescript@1.0.17
cultofcoders:mocha@2.4.6
dburles:collection-helpers@1.1.0
dburles:factory@1.1.0
ddp@1.4.0
ddp-client@2.3.3
ddp-common@1.4.0
ddp-rate-limiter@1.0.7
ddp-server@2.2.0
deps@1.0.12
diff-sequence@1.1.0
dynamic-import@0.4.1
ecmascript@0.11.1
ecmascript-runtime@0.7.0
ecmascript-runtime-client@0.7.2
ecmascript-runtime-server@0.7.1
ejson@1.1.0
email@1.2.3
es5-shim@4.8.0
fourseven:scss@4.9.0
geojson-utils@1.0.10
hot-code-push@1.0.4
html-tools@1.0.11
htmljs@1.0.11
http@1.4.1
id-map@1.1.0
idmontie:migrations@1.0.3
jquery@1.11.11
kadira:blaze-layout@2.3.0
kadira:flow-router@2.12.1
lai:collection-extensions@0.2.1_1
launch-screen@1.1.1
livedata@1.0.18
lmieulet:meteor-coverage@1.1.4
localstorage@1.2.0
logging@1.1.20
matb33:collection-hooks@0.8.4
meteor@1.9.2
meteor-base@1.4.0
meteorhacks:picker@1.0.3
meteortesting:browser-tests@1.0.0
meteortesting:mocha@1.0.0
minifier-css@1.3.1
minifier-js@2.3.5
minimongo@1.4.4
mobile-experience@1.0.5
mobile-status-bar@1.0.14
modern-browsers@0.1.2
modules@0.12.2
modules-runtime@0.10.2
momentjs:moment@2.22.2
mongo@1.5.1
mongo-dev-server@1.1.0
mongo-id@1.0.7
mouse0270:bootstrap-notify@3.1.3
natestrauser:select2@4.0.3
npm-bcrypt@0.9.3
npm-mongo@3.0.11
observe-sequence@1.0.16
ordered-dict@1.1.0
ostrio:cookies@2.3.0
ostrio:files@1.10.1
practicalmeteor:chai@2.1.0_1
practicalmeteor:loglevel@1.2.0_2
practicalmeteor:mocha-core@1.0.1
practicalmeteor:sinon@1.14.1_2
promise@0.11.1
raix:eventemitter@0.1.3
random@1.1.0
rate-limit@1.0.9
reactive-dict@1.2.1
reactive-var@1.0.11
reload@1.2.0
retry@1.1.0
rocketchat:streamer@0.5.0
routepolicy@1.0.13
service-configuration@1.0.11
session@1.1.8
sewdn:collection-behaviours@0.3.0
sha@1.0.9
shell-server@0.3.1
socket-stream-client@0.2.2
softwarerero:accounts-t9n@1.3.11
spacebars@1.0.15
spacebars-compiler@1.1.3
srp@1.0.12
standard-minifier-css@1.4.1
standard-minifier-js@2.3.4
templating@1.3.2
templating-compiler@1.3.3
templating-runtime@1.3.2
templating-tools@1.1.2
tmeasday:check-npm-versions@0.3.2
tmeasday:test-reporter-helpers@0.2.1
tracker@1.2.0
ui@1.0.13
underscore@1.0.10
url@1.2.0
useraccounts:bootstrap@1.14.2
useraccounts:core@1.14.2
useraccounts:flow-routing@1.14.2
webapp@1.6.2
webapp-hashing@1.0.9
zimme:active-route@2.3.2

my node packages :

  "dependencies": {
    "@babel/runtime": "^7.0.0-beta.54",
    "@mdi/font": "^2.5.94",
    "babel-runtime": "^6.26.0",
    "bcrypt": "^3.0.0",
    "bootstrap": "^3.3.7",
    "bootstrap-material-design": "^0.5.10",
    "bootstrap-slider": "^10.0.2",
    "bootstrap-toggle": "^2.2.2",
    "clone": "^2.1.1",
    "csv-parse": "^2.5.0",
    "d3": "^5.5.0",
    "file-saver": "^1.3.8",
    "fs-extra": "^3.0.1",
    "gm": "^1.23.0",
    "jquery": "^2.2.4",
    "jsondiffpatch": "^0.3.11",
    "lodash": "^4.17.10",
    "meteor-node-stubs": "^0.4.1",
    "mkdirp": "^0.5.1",
    "object-path": "^0.11.4",
    "popper.js": "^1.14.3",
    "select2": "^4.0.4",
    "select2-bootstrap-theme": "^0.1.0-beta.10",
    "simpl-schema": "^1.5.3",
    "uuid": "^3.3.2",
    "xmldoc": "^1.1.0",
    "zip-local": "^0.3.4"
  },
  "devDependencies": {
    "chromedriver": "^2.40.0",
    "gulp": "^3.9.1",
    "selenium-webdriver": "^3.6.0"
  }

if you have any clue about what is going on ? i can give more informations about what's happening in the app, but right now a simple explain about what this error mean would be awesome already. as i said, this error only append in 1.7.