Hi Eddy,
Please do a search in this forum on .gfp to find out how often it is mentioned.
Garmin uses their own proprietary data format for navdata and isn’t possible for us to update. We have tried to reach out to Garmin in the past but so far nothing has materialized.
The Garmin flight plan format is evidently an XML format. We haven’t developed a Charts export for it mainly due to lack of demand, and potential incompatibility with flight plans created with latest navdata running in FMC’s not updated to latest navdata. Please see Flt Pln Exporting to Reality GNS - #4 by skysail
Glad to hear you have a workaround.
Cheers
Ian