createdContractAddress intermittently shows a different contract address from the one deployed on the network

`createdContractAddress` in `txutils` will sometimes show the correct contract address but sometimes show a different contract address from the one that actually gets deployed.

Any ideas on why this is happening? You can test it out on a private testnet and about 10-20% of the time the contract address does not match the one that gets deployed.

Start by inspecting the txutils implementation of createdContractAddress and reproduce the mismatch on a private testnet, comparing the reported address with the address actually deployed on the network. Trace the intermittent cases and identify why they diverge; done means the cause is understood and the reported address consistently matches the deployed contract.

Written by the indexing model from the issue text.