This has been a major issue for us too. Several times, our Realm has been reverted back 30 minutes to several hours in 1.17. I have liked using Realms for the past few years (other than frequently being down in the past), but this is completely game breaking and we have lost so much progress.
We had this happen today too. Our Realm was rolled back about 3-4 hours ago, and all progress made during that time was lost. There is a gap in the backup log during this time too.
Angelica Pickles 
REALMS-8432
This has been a major issue for us too. Several times, our Realm has been reverted back 30 minutes to several hours in 1.17. I have liked using Realms for the past few years (other than frequently being down in the past), but this is completely game breaking and we have lost so much progress.
We had this happen today too. Our Realm was rolled back about 3-4 hours ago, and all progress made during that time was lost. There is a gap in the backup log during this time too.