HA scripts & devices disappear from Alexa and Alexa routines stop working

I have a large number of routines in Alexa that are meant to trigger HA scripts or operate devices. The scripts and devices had been discovered by Alexa and appear under smarthome/scenes. I have been adding these entities in actions in response to many voice commands.

Now, many of these scripts and devices have been unaccountably disappearing from the ‘scenes’ or ‘lights’ tabs. Worse, their references in the many routines I created have also disappeared. I can re-run discovery and the entities return, but all those references are lost. Some few routines and devices are not disappearing, but I cant discover what distinguishes those. The same may also be happening with lights, plugs and other categories.

I am using IOS app and HA is recently up to date.

how are you connecting alexa to HA?