After drinking from a fountain my character was polymorphed into a silver dragon. Before shifting I was fighting defensively, so I tried to disable it using X. Simply pressing the button immediately crashes the game without any warning or error. The cancel menu works on all other save files.
In an attempt to re-create the glitch on a fresh install I encountered an interesting issue in that simply loading the file crashes the game. The only way I could open it is by first loading a different character, quitting and loading the glitched save. The issue is still present. In addition, that Incursion install is now behaving strangely and sometimes crashes even when loading fully functioning saves, though the original install still works fine, so it's not a major issue.
Save file, backup and DMP are attached.
EDIT: Waiting until the polymorph effect runs out returns the cancel menu to a fully functioning state.