I'm running into this issue in KSP 64-bit where every time I have a decoupler on my craft, it's stuck in place until all decouplers are staged. I've tried this with all the RP-1 compatible decouplers from the starting node in my mod list, which I have provided here. This is the craft I was using, but I tried a few different things to see if I could get it to work. If you need my log, here it is. Lastly, I use a Lenovo G50 laptop with a Windows 8.1 operating system. If anyone can figure out what might be causing this, please let me know.