I believe the grind dial and single/double grind selector are essentially a fancy way of adjusting the grind time. Pretty weird if adjusting these genuinely makes no difference - have you tried going from minimum - single grind & lowest on the dial - to maximum, double grind & highest on the dial and weighing the comparative output?
I'd wholly believe clicking the dial a few notches up or down could give the same dose - it's not very accurate 🙂 - but going from min/single to max/double should show a fair few grams difference.
If it really is the same then I can only assume something's gone tits up with its internal electronics. Probably a warranty job if still under warranty?
Alternatively similar to
@MWJB's suggestions, get some cheap precision scales and either weigh the beans before grinding manually - essentially using it as a single dose grinder - or weigh the dose into a cup instead of the portafilter.
I do the former when making a quick espresso with my BE and it's not too bad - there is quite a bit of retention in the BE grinder, but it's consistent enough for everyday coffee. I gave up on using the grind presets a while ago as they're just too inaccurate - made it almost impossible to dial in reliably.
