How to manage/modify speed constraint to avoid AP disconnects


I am still trying to sort out the AP disconnect mid-flight and it is connected to the speed slowdown. On a flight plan the waypoint jumps from a speed constraint of 250 to 130 for next waypoint. Fenix flight full AP tries to manage that and starts to decrease the speed.

The yellow/red areas for speed at this time are around 180 and as expected the plane is trying go down to its target of 130 and hits the yellow limit of speed, AP disconnects.

Question - when doing a plan, is that too much of a jump 250/130 and if so how do you manage that? Sorry newbie here but I think that the speed limit (yellow/red) will only adjust as you start to add flaps? but this is an AP mid-flight during DES but I have that set to managed as well.

Thanks in advance