G500/G600 TXi products with software versions 3.10 and later, interfaced to a GNS 4XX/5XX WAAS navigator capable of GPS approaches and a DFC90 digital autopilot are affected.
The G500/G600 TXi does not allow the DFC90 to properly arm and activate GPS approach mode.
Be aware the system does not allow coupled precision RNAV approaches.
ILS/LOC/VOR approaches work as intended.
This issue will be fixed in a future G500/G600 TXi software release.