Describe the bug, provide any errors
This has started since the 1.17 update (we updated ViaVersion, ViaRewind and ViaBackwards on our servers).
Our server backends are 1.12.
Pretty much if a 1.8 client logs into our 1.12 server, all of the 'Future Blocks' just appear as air (rather than being translated into something visible for that client).

For example this screenshot is taken on a 1.12 client https://gyazo.com/3c609e8716c677cad292841fd2b74ea3
And this screenshot is taken on a 1.8 client https://gyazo.com/1d42eb720137e6991908d12ef4b85169

How can we reproduce it?
Steps to reproduce the behavior:

1. Use server version1.12.2
2. Use the latest ViaVersion, ViaRewind, ViaBackwards (the ones that were just released for the 1.17 updates)
3. Place a 1.12 block (for example Purpur block)
4. Login using 1.8 client (and you will notice it is invisible)

Expected behaviour
The blocks should get translated to something that is visible for that client version.

ViaVersion Dump:
https://dump.viaversion.com/59f401d2029b9c9a36786b80a8d0745577a0d01a5225ee60bf92adb2573977b9

Additional server info
Yes - We use LilyPad

Checklist (mark with [X] to check)

• I have included a ViaVersion dump
• If applicable, I have included a paste (not a screenshot) of the error
• I have tried a build from https://ci.viaversion.com/ and the issue still persists
• I have looked at https://www.spigotmc.org/resources/viarewind-legacy-support.52924/ and it does not offer a fix for my problem

IMPORTANT: Follow the Checklist or we can't reproduce your issue and your issue will be close

is it described by #303 ?

Looks like a dupe of #303