When network fees are considerably low such as when working in s.devnet.rippletest.net the network fee throws the following exception: "Xrpl.Client.Exceptions.ValidationException: xrpToDrops: value '0.0000012' has too many decimal places." which traces back to here:

I will submit a pull request to resolve the exception by rounding out the invalid insignificant drop decimals which maxes out at 6.
When network fees are considerably low such as when working in s.devnet.rippletest.net the network fee throws the following exception: "Xrpl.Client.Exceptions.ValidationException: xrpToDrops: value '0.0000012' has too many decimal places." which traces back to here:
I will submit a pull request to resolve the exception by rounding out the invalid insignificant drop decimals which maxes out at 6.