Power BI dataset shortens strings

I have created a PBI dataset that I published to the service. I then created a paginated report that uses that dataset. In desktop the dataset is defined as XML and it is based on http://localhost/endpointname. The ednpoint delivers just one column. I am checking its length and it is about 60K. In the paginated report the data source looks like this:

and datasset that is based on thta data source looks like ths:

My problem is the length of body field is not 60K anymore, but rather 32766.

That is a huge problem if the problem is by design. Please help me here.

Thanks