Hi Kumasasa, I looked at your set up, the issue occurs when the minecart in immobile on a detector rail. When it moves passed it (like your setup), it works fine. I've attached a link to the map in which I set it up so the bug can be observed. (If you wish more information/proof to confirm, I am willing to create a video, though that may take me some time.)
Maxence Weyrich
Hi Kumasasa, I looked at your set up, the issue occurs when the minecart in immobile on a detector rail. When it moves passed it (like your setup), it works fine. I've attached a link to the map in which I set it up so the bug can be observed. (If you wish more information/proof to confirm, I am willing to create a video, though that may take me some time.)
Drop Box link to map: https://db.tt/hqiTEoVq