Ember.js select fetching api data: different behavior on Chrome/Firefox

I have a form with some selects (components which have to fetch api data to populate the select)

In Firefox, all is fine, the selects are populated correctly and the correct value is selected.

In Chrome, some selects are populated fine, some are missing values, some are empty. Those which are populated correctly have the correct value selected. In console, I see errors of strange api calls returning 404, like api/poles/1 (which is the selected pole value, but as the select is empty it couldn't be selected) and api/agencies/2 (which is the selected agency value, and as the select was populated correctly the value is correctly selected).

Even though pole and agency are both belongsTo() of the current route model, api/poles/{id} and api/agencies/{id} do not exist, but there are other models where such calls exist and those don't trigger the problem in the selects (but can still have missing elements...)

Looks to me like 2 separate problems (one for the mispopulated selects, one for the 404 api calls for selected value) that do not happen in Firefox though.

Sadly the component code is a bit complex, with a service involved, but is there any specific direction I should go to debug this? Do the symptoms ring a bell to anyone?