HEVC 4K videos (mp4) are played smoothly and smoothly from the library. As soon as the clip is in the timeline, it no longer works. The preview quality does not matter here. Everything went smoothly in the software version from June (I went back to testing). It couldn't be due to PC performance (Core Ultra 9 285 | 64GB | NVIDIA GeForce RTX 5070 Ti) and it worked. Can anyone understand this or has a solution?