Xubuntu (Ubuntu) 16.04, Nvidia GTX 720
When using dyntopo in sculpt mode, pressing ctrl+z (undo) wipes all progress from the sculpted mesh - but progress (minus the last change) returns after doing any action (ie. moving viewport angle).
Open Blender. Go to Eevee. Add mesh. Go to sculpt mode. Turn on dyntopo. Sculpt something quick - using multiple strokes. Press ctrl+z (undo). All progress should disappear. Do something (ie. move view angle). Should return. Probably also related to T52246.