A world that has successfully survived moving between several snapshots since 1.15.2 has gone rogue when I updated my client to 20w17a today. As far as I understand this is due to the Block Storage tweaks that arrived with this snapshot. I could continue on with 20w16a for I didn't progress too far before noticing the corruption, but if the matter can be helped I would be happy beyond measure.

To be precise, the world looks completely fine, but all the maps show some weird stone strips across the landscape (as can be seen on the screenshot) and rain falls through solid blocks. That may not be the full extent of all the "features", but it's enough.

Can we expect this to be fixed in future snapshots or is any world created before 20w17a now done for?