@146Whisperer Apologies for the belated reply. I have just tried this on my Xbox Series S and I am not able to replicate any crashing issues when pressing "send" on the Datalink > Weather page. Are you perhaps running the MSFS Sim Update 15 Beta? That may explain the difference we are seeing.
Nevertheless, the FMS currently fitted to the 146 Professional was developed by Working Title, so unfortunately we are very limited with what support we are able to offer for it on our end. Talking to our development team, there may be an updated version of the Working Title FMS that we can update to in the next update to the 146 Professional, so this may fix the crashing issue you are seeing. If it doesn't, it would be something the Working Title would have to investigate on their end.
Mark - Just Flight