Node-red-node-email fails with attachments 0.1% of the time

I'm using node-red-node-email to send a daily report with graphs and such. Because outlook is... well... challenged, I have to attach images of graphs instead of linking to them. I would like to learn how to achieve this at a later time but for now attachments work fine 99.9% of the time. When they don't I get this message:

TypeError: The "chunk" argument must be of type string or an instance of Buffer. Received an instance of Object

The only way I have been able to resolve this is by uninstalling and reinstalling the node. I cannot follow the code well enough to determine where this failure happens, but this seems to be something internal to the node and I'm not able to manipulate the "chunk" argument directly through node configuration or message properties.

Anyone have any experience with this issue?

Are there more error lines around that in the log ?

Sorry, none at all.