Well 1stly would recommend you move sensors further from the GW’s! (or move the GW’s away from the sensors). If at just 1m you are pretty well operating in near-field vs far-field mode (typically look to be >>4/6 full wavelengths away) and then precise placement can be an issue. Also at such close range you may well be overloading the front end. I know most GW manufactures recommend running any nodes operating at full power (14dbm ERP in EU, potentially >>20dbm in US and elsewhere) be placed at least 2m away from GW antenna to avoid issues. By saturating its poss LoRa message may ‘appear’ on several channels causing GW demux confusion and lost packets/CRC errors causing NS to drop etc.
Looks like the two styro-foam mounted antena’s route to the Telit Cellular card? (don’t have one to hand to confirm - but orthogonal layout suggests may be the case). Suspect the LoRa antenna is the strip close to the edge of photo opposite the Cellular modem?
Even such a weak antenna (compared to external co-linear, dipole or monopole x-dbi unit will likely capture enough signal to cause issues.
Would suggest realistic test is to place say 5-10m+ away in both instances…