There was an issue with the bandwith calculation formula, and a softfork patch 19.1 has been released by the dev team. Some nodes are still running 19.0, so you may still occasionally get a bandwidth error if your transaction hits a 19.0 node. Within a few days, hopefully most of the nodes will be upgraded to 19.1 and the error will go away. In the meantime, if you get an "exceeded bandwidth" error, just try again in a little bit.
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