Host web ribbon custom action randomly disappears

Hello,

I've been developping and running for a year a SharePoint app (target environment is SPOnline through AppCatalog) in which a custom action is defined so that users can share files. In order to have a consitent UX, I placed it into the "File" ribbon tab, in the "Share" action group.

However I have been having a problem since around June 2015. This ribbon action disappears randomly. The app package have never been updated on this timespan nor the app instances themselves have been tampered with.

So far the problem have only been confirmed on one tenant. Also, I have two versions of the app package (demo and prod) that have a different ProductId and app name, both showed the same problem.

The only way to get my ribbon custom action back is to Uninstall/Install the app all over again, this is not sustainable.

Did you have a similar problem and if so what would be the cause/solution to it ?

Here's the custom action definition, if it can help:

<CustomAction Id="0783bd57-cfce-4ee1-bc7c-1add1c99f056.RibbonAction"
                RegistrationType="List"
                RegistrationId="101"
                Location="CommandUI.Ribbon"
                Sequence="10001"
                Title="$Resources:Title"
                Description="$Resources:Description"
                HostWebDialog="TRUE"
                HostWebDialogHeight="800"
                HostWebDialogWidth="790"><CommandUIExtension><CommandUIDefinitions><CommandUIDefinition Location="Ribbon.Documents.Share.Controls._children"><Button Id="Ribbon.Documents.Share.RibbonActionButton"
                  Alt="$Resources:Alt"
                  Sequence="100"
                  Command="Invoke_RibbonActionButtonRequest"
                  LabelText="$Resources:Label"
                  Description="$Resources:Description"
                  TemplateAlias="o1"
                  Image32by32="$Resources:Image32"
                  Image16by16="$Resources:Image16"
                  /></CommandUIDefinition></CommandUIDefinitions><CommandUIHandlers><CommandUIHandler Command="Invoke_RibbonActionButtonRequest"
                         CommandAction="~remoteAppUrl/MyController/MyAction/?{StandardTokens}&amp;SPListItemId={SelectedItemId}&amp;SPListId={SelectedListId}"
                         /></CommandUIHandlers></CommandUIExtension></CustomAction>