On my 2020 GLC 300 4Matic noticed multi-function steering wheel touch pad will not swipe left or right, or up/down (you can push and get display to work that way like seeing previous routes, set route guidance/cancel guidance etc - mine is stuck on Navigation).

Touch Control on left side steering wheel controls on board computer functions:

Drive Assist
Trip Navigation
Radio
Media
Phone
Head-up Disp.

To scroll through displays or lists on the menu: swipe upwards or downwards on left hand Touch Control.

Other than going to MBUX-Settings-Reset not sure how to fix this issue (doing so will delete all my data). Called my servicing MB dealer and have appointment/loaner for August 2nd.
Personally I think an OTA software update borked the functionality of the left side touch control.

If anybody has ideas or suggestions please let me know. Thanks.

Customer Care advised cleaning touch control pad with microfiber - I tried that, compressed air and Nice'N Clean screen wipes and no luck. Advisor said they most likely remove steering wheel cover, check for loose connection and most likely replace the touch control pad to fix.

I believe your VIN has one pending MBUX recall. Online https://www.mbusa.com/en/recall shows 2021070011 I find 2021050012, same subject matter. Indeed OTA update could have caused malfunction but best to have dealer follow up software update with Xentry. Although not directly related to your problem, as a matter of reference, here are applicable bulletins released. Capture shows switch panel part # (if needed).

Thanks for the detailed, informative reply. Part #360 is like a ghost - service department found one in the U.S. I had viewed status of my vehicle's recall OTA updates but appreciate your feedback.

Will ask for Xentry check, unfamiliar with it. Google/Wikipedia showed diagnosis system that is used to troubleshoot Mercedes-Benz car problems and is the official Mercedes-Benz dealer software.

Thanks @ konigstiger!

From work order 08/03/2021:

CLIENT STATES THE LEFT TOUCH PAD ON THE STEERING WHEEL IS NOT RESPONDING.

VERIFIED CUSTOMER CONCERN AND FOUND THAT THE LEFT TOUCH SCROLL FEATURE DOWS NOT WORK AT ALL. HOOKED UP XENTRY AND FOUND N CURRENT FAULTS RELATED TO THE TOUCH PAD. PULLED UP XENTRY TIPS AND FOUND NO DOCUMENTS RELATED TO THE COMPLAINT, PULLED UP STAR WIRING AND FOUND THE WIRING DIAGRAM FOR THE TOUCH PAD, DISCONNECTED BATTERY AND REMOVED AIR BAG AND TRIM, CHECK ALL ELECTRICAL CONNECTIONS AND GROUNDS, AND FOUND NOTHING LOOSE. RECOMMEND INSTALLING NEW STEERING WHEEL LEFT SIDE TOUCH PAD.

PARTS HAVE BEEN ORDERED, WILL BE RETURNED WHEN PARTS ARRIVE.

So my next appointment is not until 8/19! Round Trip mileage to dealership approx. 200 miles. Too bad they just did not believe me, had loaner most of yesterday..

Left control touch pad was fixed today under warrantee - along with my Service A work. It was the part not software.

Glad to finally have it working again.