Not getting push alerts for flight plan amendments

We are consistently able to receive push alerts when we file GA IFR flight plans through flight services. However, when we amend the flight plan, we are not getting push alerts for the amended flight plans. For example, have never received a push alert when Estimated Time of Departure (ETD) is amended. Have been able to receive a push alert for an amended destination, but only intermittently. Also have tried amending both destination and ETD, and received a push alert with updated destination, but the ETD in the alert was unchanged.

We have done SetAlert with all of the alert types (e_filed, e_departure, e_cancelled, etc), so that doesn’t seem to be the problem, and in addition, when we amend an IFR flight plan in our system it actually cancels the flight plan with ATC, and files a new flight plan with ATC. So we would expect to get an e_cancelled event, followed by a new e_filed event. But we are not getting any e_cancelled events, and as described above in most cases also not getting a new e_filed event for the new flight plan.

Appreciate the assistance.