UPBv2 + Motor Focus Kit does not stop running

[Staring]

For some time now, sometimes the motor focus will not stop when it is issued a goto command when moving in. It moves right past the goto point until it reaches a hard stop when the draw tube is all the way in. The focuser panel shows the focuser position correctly (I .e. something very low for "all the way in"). The problem is intermittent and happens from ASCOM and the unity panel. I've already replaced the UPBv2 (against a spare one), the cable and the PC. Any further ideas?

[Staring]

Sorry for cross-posting, but I don't know if this is an UPBv2 or a MFK issue. I found an error in the UPBv2 logs:
0000->Invalid response from device
1301->Error on invoking method [MotorMoveAbsolute]


System.Exception: Invalid response from device
at Peg.Engine.Driver.UPBv2.UPBv2Driver.MotorMoveAbsolute(Int32 steps)
at Castle.Proxies.Invocations.IUPBv2Driver_MotorMoveAbsolute.InvokeMethodOnTarget()
at Castle.DynamicProxy.AbstractInvocation.Proceed()
at Peg.Engine.EnsureDriverStartedMiddleware.Intercept(IInvocation invocation)
at Castle.DynamicProxy.AbstractInvocation.Proceed()
at Peg.Engine.DriverExceptionHandlerMiddleware.Intercept(IInvocation invocation)