I am editing .mov clips from my osmo. On my computer, when I open those files with windows media player, everything is fine. However, in Premiere, each clip has only exactly 1.5 sec of audio. I thought that it was a conforming issue, so I opened them with Adobe audition, but the same issue remains.
Does somebody here has already encountered this ?

Are you on a Mac?  I found this searching Google. OPs said it worked like a charm:
1. Launch the Audio MIDI Setup, which is located here: Macintosh HD > Applications > Utilities.
2. Click on Window in the menu bar and choose Show Audio Window.
3.In the Audio Devices window of the Audio MIDI Setup, click the Add  button.
Create Aggregate Device and change the Audio Hardware to new Aggregate Device in Premiere Pro Audio Hardware Preferences.
***  Plus the following response from someone who said it worked:
One missing step was that I had to click and select all available boxes when the Aggregate window came up. Then restart Premiere, then go to Audio Hardware and it finally showed up



Try to do Playback after that and check if it works.

Sorry that we are unable to provide any support to the third party program, you may refer to StanfordWebbie's suggestion to have a try, he has rich experience with Osmo series products.

Thank you for your answer. I am on a PC, so I fear it is not relevant for my case.
However, if someone encounters the same issue, here is how I fixed it:
I downloaded Audacity (an audio editor) and made a batched job with all the .mov files in order to extract the audio track in .wav. I just have now to synchronize audio and video in Premiere, but this not a big deal.