I exported a 30 second video from Twinmotion 2023.1.2 and a group of trees I placed disappear for about 2-3 second. Not sure why the glitch out and reappear 3 seconds later. See attached trimmed video.
Anything you do while making a keyframe will render. If you hide something then make a keyframe, that will happen in the exported video when your animation reaches that keyframe. Handy for some effects, unless you’re working on something and updating a keyframe, forgetting you changed a setting, such as hiding trees? Or it’s a bug. Click on every keyframe of your video and ensure you don’t hide the trees.