I've not seen that behavior. Do you happen to have a screenshot of what it looks like? What version of Tableau are you running?
Could you post your package workbook in order to identify the cause of the problem.
I suggest you trying to reproduce the issue and take note of the steps you do. There is not enough information in your description to figure a solution out.
it basically looks like a scatter plot where all the marks are light gray.
it's random and if I rebuild the plot, the error goes away. it's not a function of the dataset as far as I can tell because I can never recreate it. I've also had the issue occur when I do a lot of "undos".
i'm connecting live to excel files that are stored on our company servers if that matters at all.