Problems with recieving position data. Could it be GPS-jamming?

Recently I'm having problems with receiving position data from my InReach SE. This is the second trip this year where only a few of the presets or messages include position data. All settings on the garmin explore page should be good, the device is updated and synced. We've even tested the device multiple times before the trips with success. But when we move up in the mountains, we lose almost all position data.
I have a suspicion of the cause of the problem: The two trips were done in Finnmark, Northern Norway, relatively close to the Russian border. There has also been reports of problems with GPS-jamming for airplanes over Finnmark the past few years. Could this be the cause of the problem for my InReach? Or, is there any possibility there could be something wrong with the device? Is there any record of InReaches failing in this way?

This is kind of problematic, because without knowing the cause of the issue, this is a very unreliable system.

  • Anything is possible. However, the most likely reason for loss of fix in mountainous terrain is loss of (part of) they sky view and/or multipath.

    Offhand, I do not recall if these legacy devices warn you if you attempt to send a message without a fix. If not, you're going to have to manually verify that you HAVE a fix before sending a message.

    Most iR devices will record a sent track point more or less "on time" regardless of fix status. They will try fairly hard to acquire before sending a point without location. But they will not wait forever. So it is possible to see sent points without coordinates.

    Since the device reports correct coordinates when tested in "ideal" conditions, it is not likely to be the device. 

    For any iR device which has problems acquiring/maintaining a fix OR problems sending/receiving via the iR satellite network: The conventional wisdom is to carry the device high on your shoulder (for example, on a pack strap). This improves sky view by eliminating block by your body (as much as possible). Do NOT carry the device in your pack, in a jacket pocket, in a pants pocket, etc.

    Also note that many newer iR devices are multi-GNSS, which might improve fix acquisition in challenging conditions.