I found a solution or workaround (by chance) to that problem. You can in fact capture multiple videos with the camera app, but you have to switch to 'camera mode' and back to 'video mode' after each recording. Then you're good again for one take.

"ceterum censeo": The Nexus 5 has become a quiet reliable toy with SailfishOS. I call mine 'Pris'... a basic Nexus pleasure model.