Poor software design, and choices that you later regret.
We have real examples. Remember the Y2K bug? Did you know GPS has a mini-version of that bug, that affected lots of devices in April 6, 2019?
That's because GPS satellites uses ten bits to represent datetimes in their broadcasts. They can only represent timespans of about 1,024 weeks. So starting from whatever date and time they consider zero, they can count up to nineteen years and a few months. For comparison, modern softwares like nowadays browsers use 64 bits to represent date and time. Most of Microsoft's software can handle dates from 00:00:00 in January 1, gregorian year 1 to 23:59:59.9999999 UTC, December 31, gregorian year 9999.
GPS was designed to use only ten bits for dates and times because it is cretaciously old, for computer standards - it was released in 1973. And the system has been working well enough, and devices get obsolete fast enough that people would rather reset the "datetime zero" every nineteen years rather than fix this "flaw". They've had plenty of opportunity - the oldest GPS satellite in operation was launched in 1997. It would be pretty easy to add more bits to the datetime - each bit doubles the span of dates that can be represented. But no one wants to fix what is not broken.
Prior to April 6, 2019, the "date zero" for GPS was August 21, 1999. On April 6, 2019, all devices that could not update their software started thinking they were receiving satellite broadcasts from that "date zero". And broadcasts from April 7, 2019 were processed as being from August 22, 1999. April 8, 2019 was understood as August 23, 1999 and so on. At best the affected devices would show wrong dates in their user interface, but mostly they ignored the GPS broadcasts after comparing the broadcast date with their own internal clock. Ignoring all GPS broadcasts means you cannot get a reading so you won't know where you are.
And you know what kind of devices could not be updated? Think TomTom and Garmin handheld GPS devices that have no Wifi connectivity and no USB port, and which some people love to use when doing tourism because they won't learn how to use an Android or iPhone.
Devices like this:
And even when they do have the port or connectivity to update, the company will force users to buy new hardware or be left without updates. This happened in 2018.
Now imagine your characters in the desert planet. The planet has a satellite network that worked fine for some period - maybe millenia, maybe even longer eras. It just happens that the satellites have hit the maximum date they will hold in their memory. At the next tick, they will reset to their date zero and start counting from there.
Worse, their date zero is out of the range your characters' devices can use. And they don't have access to the satellites control system, or maybe updating their dates will cause something else to fail. And the only place where you can buy new hardware is a few star systems away. Your characters may develop some hatred towards IT professionals from the past.
Don't want to get too technical with programming and binary code? Just say some bug happened that is causing issues.
Or use something else to make the satellites dysfunctional. Maybe they require a password that you don't have. Maybe a prank went wrong and the satellites have been trying to calculate the last digit of Pi for millenia. Maybe the poles of the planet shifted and the compasses on the satellites aren't handling it well, so they are pointing their dish antennae to the wrong hemisphere.