I am having issues committing Attachments from the ServiceFeatureTable to the FileGDB via ApplyAttachmentEditsAsync(). I am able to add and then retrieve it successfully through the AddAttachmentAsync/QueryAttachmentsAsync calls (ie SFT operations locally work). I am able to query attachments added to the feature class via ArcMap as well (ie attachments have already been enabled via arccatalog). ArcGISFeatureTable.HasAttachments, and ArcGISFeatureTable.CanAddAttachments(Feature) both return true. However invoking ApplyAttachmentEditsAsync returns a Result.Error : "Response status code does not indicate success: 500 (Server Error).". The log isn't particularly clear either.
I noticed a possibly related bug with ApplyAttachmentEditsAsync in the 10.2.7 release notes, however when I rolled back the Runtime SDK version to 10.2.6, I was getting the same issue so I don't know if they are related. Is there a workaround?