I have recently started having a problem with the volumetric dosing on my M29 Select. The shot extraction starts, and then the machine seems to think the volume has been reached and clicks off and then immediately started delivery again. Kind of like a stutter. The problem occurs regardless of the presence or absence of coffee in the filter and happens on both groups. However, the problem is not consistent. Some days it is severe, other days no problem at all.
Any ideas what might be causing this? I can make and post a video next time it happens if that would help.
Thanks for any tips.