Truncated fork version hex results in corrupted data

[samczsun]

$ git --no-pager diff
diff --git a/server/utils.go b/server/utils.go
index 020b64d..43c2c5d 100644
--- a/server/utils.go
+++ b/server/utils.go
@@ -86,6 +86,7 @@ func ComputeDomain(domainType types.DomainType, forkVersionHex string, genesisVa
        }
        var forkVersion [4]byte
        copy(forkVersion[:], forkVersionBytes[:4])
+       fmt.Println(hexutil.Encode(forkVersion[:]))
        return types.ComputeDomain(domainType, forkVersion, genesisValidatorsRoot), nil
 }

$ go run main.go -relays https://0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000@example.com -genesis-fork-version 0xabcd
INFO[2022-08-30T01:24:39-07:00] mev-boost v0.7.11-dev                         module=cli
INFO[2022-08-30T01:24:39-07:00] Using genesis fork version: 0xabcd            module=cli
INFO[2022-08-30T01:24:39-07:00] using 1 relays                                module=cli relays="[{0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 https://0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000@example.com}]"
0xabcd6364
INFO[2022-08-30T01:24:39-07:00] listening on localhost:18550                  module=cli
^Csignal: interrupt

hexutil.Decode uses hex.DecodeString internally which reuses the input buffer:

https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/encoding/hex/hex.go;l=118-124;drc=7f92ccea5ca5832a1dc63c02fc71db2d698f7915