A look at getpeerinfo reveals clients that have mixed subversions, all of which also have the starting height around 584426 blocks.
/DGC:2.0.0/
/WorldcoinFoundation:0.8.6.2/
/42:0.7.0/
/MemeCoin:2.2.0/
There are currently only a handfull clients, one of which is the block explorer that has the correct starting height and is also on the (correct) client version.
/Satoshi:0.6.3/
To stop your client from connecting to these rogue peers and seeing your wallet get out of sync, you need to edit your royalcoin.conf file and connect directly to the good peers. Using connect instead of addnode will prevent the other peers from connecting.
connect=50.128.154.237
connect=63.170.87.173
connect=70.164.233.141
connect=70.164.233.143
connect=173.238.180.157
connect=204.11.237.73
connect=108.172.121.86
These have the correct starting height at around 54294.
This is only a temporary fix until the client is updated.
unsigned char pchMessageStart[4] = { 0xfb, 0xc0, 0xb6, 0xdb }; // Royalcoin: increase each by adding 2 to bitcoin's value.
unsigned char pchMessageStart[4] = { 0xfb, 0xc0, 0xb6, 0xdb }; // MemeCoin: increase each by adding 2 to bitcoin's value.
unsigned char pchMessageStart[4] = { 0xfb, 0xc0, 0xb6, 0xdb }; // Worldcoin: increase each by adding 2 to worldcoin's value.
the peerMagic can't be changed without destroying the block chain.
The easiest fix would be to set the client/subversion name to RYC or Royal and only answer/accept other clients that have the same subversion name.
then each time a checkpoint is needed the client could be set to answer/accept other clients that have the same subversion name and build number.