When I'm loading chunks they disappear sometimes. It happens only if I'm walking somewhere far like 200 blocks it happens and won't stop if I don't stop. It's hard to explain so I recorded a video. It happens even with already generated area where I've been before.
Time where bug start to appear 0:25 0:45
Please check if that's still an issue for you in the latest 1.14.4 stable release or the latest 1.15 development snapshot.