In my research on occupation, war, and liberation in the southern Netherlands, I have come across situations in which men of the German armed forces have deserted and who, upon capture, were executed for it. These cases became more frequent as the Allies, and especially First Canadian Army, pushed north from the Leopold Canal in autumn 1944. Dutch historian Hans Sakkers also discusses these executions in a recent book called Duitse militaire standrechtelijke executies in Zeeland, september- december 1944 (Soesterberg: Uitgeverij Aspekt, 2013). Unfortunately, the book is only available in Dutch.

If you are searching for cases in which German troops absconded their units/formations, I would consider using the term desertion rather than mutiny. A mutiny often implies a more large-scale rebellion against an officer or leader. In this way, an exploration into desertion may yield more promising results.

Additionally, it is important to remember that depending on the German unit/regiment/army, formations changed throughout the war and some were reinforced by Poles, Soviets, Italians, and various other ethnicities. For example, when elements of First Canadian Army defeated German forces in the Schelde in October-November 1944, the Allies were surprised to see Moroccan and Soviet troops among those Germans who had surrendered.

There's a fantastic book called Slaughter at Halbe which describes the final days of the war for the German Eight Army. Hitler had ordered them to defend an indefensible position near Berlin against the Soviet forces, and so in order to escape Soviet justice they attempted to break out through to Allied lines. This for the most part failed, inflicting thousands of casualties.