Update reply below contains reproduceable steps to create objects showcasing this bug from scratch; original post in this post left for posterity. The issue appears to involve a Multiresolution modifier with subdivision levels causing a crash when attempting to sculpt the relevant object but only in the case where a specifically configured Mirror modifier had been copied and applied after creation of the Multiresolution modifier.
Operating system: Windows 7 Ultimate - Version 6.1.7601 Service Pack 1 Build 7601
Graphics card: Nvidia GeForce GTX 950
Broken: 2.80, 2.81 release
Short description of error
Trying to use sculpt tools on a specific object in my file ("sculpt_figure res2 breasts") causes Blender to crash. I had not encountered any crashing issues involving sculpting up until I tried sculpting this particular object. The crash reproduces on multiple systems. I have attached the blend file in question.
Removing either the Multi-resolution modifier or the Armature modifier from this object ("sculpt_figure res2 breasts") allows the object to be sculpted without crashing. Adding a new Multi-resolution or Armature modifier after either modifier has been removed also allows sculpting without crashing. The crash only happens when attempting to sculpt the object as is without removing and/or re-adding said modifiers.
The object in question ("sculpt_figure res2 breasts") was created by duplicating the object "sculpt_figure res2" and removing a selection of faces from the duplicated mesh, adding edge creasing to edges in the duplicated mesh, applying a mirror modifier belonging to the duplicated mesh, and adding a multi-resolution modifier to the duplicated mesh. I am not certain the order in which these actions were performed.
Exact steps for others to reproduce the error
Open the provided file "sculpt8_2.blend."
Select the object "sculpt_figure res2 breasts" in the "sculpt" collection if not already selected.
Enter sculpt mode.
Select a sculpt tool (tested with Draw brush, Thumb brush, Mask brush).
Click the sculpt tool on the mesh to attempt sculpting