a string was found that was larger than the page size selected

[turboviz]

We are developing a custom visual to render a graphic based on an encoded value of a single cell in a data store.  That is, the value to be passed to the custom visual is essentially a large string of typically ~200Kb.  What I have discovered is that there seems to be a limit on the size that can be handled by PowerBI (around 64Kb – depending on the data source?). 

Any ideas would be appreciated!