Happens to me constantly as well, sometimes this includes a rollback. I have lost materials and died repeatedly while mining because of this. It is intolerably atrocious. It happens CONSTANTLY. We're talking like, at minimum once an HOUR. Like Scott above, I also rolled a new realm, I now have THREE realms, and they ALL do the same thing - constantly. This is not a client problem, this is a server architecture problem. In the case of two of my realms (the 10-person ones) I was the only person playing and this happened. It's not some client corruption because of bad textures or something absurd like that. Vanilla install, store purchased skin and texture packs, brand new realm with only one person on it, and it crashes non-stop. For $8 a month.
The Affects Version/s entry is incorrect - affects windows 10 beta edition realms verson 1.15.7 (currently). There is no match for this version number under Realms project.