Hi…,
Welcome.
In order for us to assist, can you be more specific. Are you talking flight plans generated in Simbrief or Navigraph Charts. Are you loading it into the Navigraph Charts In-Game panel, or into Charts Desktop or Charts Cloud.
Please upload a flightplan causing the issue.
Please post screenshots showing where SID/STAR’s were, then a re missing using Guide to posting Screenshots
Note, when you load a flight plan into MSFS then change your gate, MSFS recalculates your flight plan. See Flightplan getting mangled going into MSFS - #3 by Ian
Cheers
Ian