Hi Sérgio Sant'Anna,
Thanks for using our Syncfusion products,
In our Volume 2,2018 release, we have included support with Reportviewer to increase the size of the text box report item based on content by using third party SkiaSharp library to measure the text size. Based on the below article, SkiaSharp may causes the issue with self-contained deployments
https://stackoverflow.com/questions/47436789/understanding-net-core-and-mono
(You can still run into problems if a used DLL references a native-dll (that it provides as embedded resource), but does not provide the necessary C-Runtime-libraries (e.g. when the native-dll/.so is dynamically linked - such as in SkiaSharp).
As of now, you can avoid this issue by changing Cangrow property as false for Textbox report item. We will check the possible cases and address this issue in our Volume 2,2018 Service Pack release and can be expected in end of this month.
Regards,
Lingaraj S.
Thank you for information.