FIndexedCurve::KeyHandlesToIndices is not replicated, and so seems to be permanently out of date. This isn't readily apparent when there are more keys than the default amount, but when removing keys it becomes an obvious issue.
Note, this issue is also present when playing. Adding a break point inside BeginPlay and inspecting the curve will show that KeyHandlesToIndices only contains the number of items setup in the constructor.
Expected: There should be one value on the curve.
Actual: There are two values on the curve display. One is at (0,0) and not connected, the other is the appropriate value.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-35463 in the post.