I am using FS24 with Navigraph. It seems that the Avionic plug-in (G1000) causes problems ‘most of the time’. It is possible to import a flight plan, but it is not displayed in MFD Magenta. The CDI and sequencing are also incorrect: the course always points north and the deviation bar is always centred. In addition, a grey round circle appears instead of the aircraft symbol on the MFD, but this then changes to an aircraft symbol. It is also strange that I can always select two identical approaches in the PROC (twice).
It sounds like you are having issues related to several other topics in this forum. So far, all the others have been caused by the simulator not reading our navigation data in the correct order, which is causing issues inside the simulator when doing things related to navigation data (such as importing a route and selecting a procedure for example).
Please have a look around - for example in this topic:
For the record: I am not able to reproduce this issue with only our navigation data and avionics plugins installed. However, based on feedback from others, it could be a hit or miss scenario where it works some simulator starts and sometimes not at all! We are actively investigating this, but we have yet to find a working solution after several attempts.