One thing I noticed is that the version of FCR embedded in MSFS 2024 is not the same as the version of the external app in its latest version. It’s either an old version or a stripped-down to improve compatibility.
I noticed this with the Fenix A320. The embedded FCR is not compatible with the Fenix. If you try to play a replay with the Fenix, all the aircraft animations will appear bugged, even the landing gear. However, the external FCR plays the Fenix replay normally, with all the animations working.
Another thing that bothers me with the embedded FCR is that there is a bug when you either minimize or close the FCR window in the sim after pressing the record button. As soon as you finish recording and want to stop, when you try to open the FCR again, the window remains minimized and I can’t maximize it, even pressing the maximize button several times. Sometimes it maximizes after several attempts and other times it doesn’t.
At the moment, I prefer to use the external FCR app for replay.