gradient issues again after 31.31

I can confirm there is a BIG firmware issue, affecting the pressure sensor/altimeter. After checking the air pressure intake, reseting the device to factory defaults and all kind of tries, the problem persists. The version completely ruins the gradient data ! Please Garmin , solve this or I will send my device back to repair center because a firmware issue.

In my case, after the update 31.31 and I tried the hard reset, then I went for a ride the day after and then the gradient was accurate again. I was happy that it was working already but after 2 rides it did not worked again, it was inaccurate again. This is already frustrating.
My cheap XOSS G+ 2 is even more accurate.
I'm not sure if garmin is even reading our comments.

Mine did work for 2 rides only after update and hard reset and then went back to gradient inaccuracy 

I've had gradient issues with my 840 since I bought it. Sold it and bought another, same issues. On false flat or slightly rolling roads, I can barely get the gradient to go over 0, maybe 1%. Going down the other side, it will read -3, -4%. Will only start to read in positive numbers once the road starts going up for 50 feet or so, and the gradient starts getting up over 4 or 5%. No updates, or cleaning out the altimeter port have fixed this.  

Unfortunately, I had no choice but to send my Edge 540 back to Amazon's repair centre, as that was where I purchased it.

It's extremely frustrating to have to return a device for repair when all the evidence points to what appears to be a firmware issue rather than a hardware failure. However, when you spend this kind of money on a Garmin device, you expect it to work properly.

What disappoints me even more is Garmin's complete lack of action regarding a problem that so many users have been reporting for months. There are countless reports describing exactly the same behaviour, yet there has been no clear acknowledgement or effective fix.

I'm genuinely disappointed. Garmin no longer seems to represent the level of quality, reliability, and engineering excellence that made it the market leader. This situation is simply unacceptable.

Thank you for your reply, but this is exactly the kind of copy-and-paste response Garmin has been posting for years whenever users report barometric or gradient issues.

Many of us have already cleaned the barometer port, performed manual calibration, reset the device, updated the firmware, and repeated the tests over multiple rides. We are not reporting these issues after a five-minute ride without doing any troubleshooting.

The problem is that Garmin keeps treating every report as an isolated case, despite this forum containing months—if not years—of users describing exactly the same behaviour. At some point, it becomes impossible to believe that every single device has a hardware problem while the firmware is always assumed to be correct.

What is most disappointing is the apparent lack of interest in seriously investigating these reports. People who take the time to post detailed findings on this forum are often experienced cyclists and technology enthusiasts. Many of us understand how these devices work, know how to troubleshoot them properly, and can distinguish between a blocked barometer and a software regression.

Instead of receiving the same standard support article every time, we would expect someone with engineering responsibility to acknowledge the pattern, investigate it, and communicate openly with customers. That simply isn't happening.

I have now had to send my Edge 540 to Amazon's repair centre because there was no alternative. Yet I remain convinced this is a firmware issue. If Garmin finds nothing wrong with the hardware—as I suspect will be the case—I sincerely hope someone finally takes these repeated reports seriously.

Garmin built its reputation on engineering excellence and customer trust. Repeating the same scripted responses while a growing number of users report the same issue is not the standard customers expect from a premium brand.

I believe it is really a firmware issue and not hardware related. because if its hardware related, my gradient accuracy would not work for 2 days after the initial update for 31.31..I think what happed was, the second half of 31.31 update make it not work again..just my observation based on my experience on my 540.
However, what make me think is, in some areas, it seems to measure the gradient correctly or fairly correct.
Could it be that the software or firmware has synching issues with the DEM?

Exactly. If something works correctly and then, immediately after installing a firmware update, it starts producing incorrect gradient readings, it is very difficult to believe that the problem is suddenly a dirty pressure port.

That explanation simply doesn't fit the observed behaviour.

What is frustrating is not just the issue itself, but Garmin's apparent unwillingness to seriously consider the evidence that customers are providing. Instead, every thread receives the same copy-and-paste response, regardless of the facts being presented.

No one is asking Garmin to admit a firmware bug without investigating it. What we are asking is for someone to stop dismissing repeated, consistent reports and actually investigate them. 

Also to add, it is really a firmware/software issue since advance grade(1) seems to be working just fine, but please be advised that it has a 2-3 secs delay sometimes specially in urban areas.