Crashes when using masks in Scatter

In the scene i am currently working on i can not use masking on a Surface Scatter i have made with a landscape an a scattered tree. The scattering works fine, but when i try to add either a Landscape mask or an Object mask (with a spline) it thinks for a long time and then it crashes. It is v1.8.3. I have attached a screenshot after adding an object mask. Also the log file after crashing. I have some other scatterings in the same scene with bushes and gravel without problems, using splines as masking.

Cemetary.log