Maybe btc38 is migrating some user accounts into the blockchain. Makes sense since they need to use the same blockchain we do to receive/pay deposits/withdraws. This may be part of a new system their implementing. Since each account needs to pay to register, and there isn't much chance of those being a typo by someone, I doubt it is a spammer bot.
As more institutional users get on to the platform I suspect we'll see a lot more of this. At my company we have hundreds and hundreds of account codes for everything from buying office supplies to tracking building leases.