While i was building up with Oak Logs, i phased through a block and fell off. This has happened on multiple occasions and has caused me my death. I have tried it with other blocks and the same thing has happened. But the only thing i found is that you have to spend a bit in the world for it to work. From what i know it has to be at least 10 minutes for it to phase you through. I have a screen recording on this google drive link: https://drive.google.com/file/d/1CR9a4hCaKcTGb1qOv2u88pTAFDl7Rm6p/view?usp=drivesdk