Hi all,
The Outlook In App Support Team is working on escalating this issue. We already have a bug opened that we think is this issue and confirming.
It appears there is a limitation with WebView Adaptive Cards that stops at 10. For example, I can repro this issue by sending myself 10 emails with Polls (New email, Insert, Poll under Include tab). If I open each Poll email and keep it opened I will usually get the error on the ~10th Poll email. The Poll is based off of Actionable Messages.
If you are seeing this with a different Actionable Message, please let me know what that is? I will post back when I know this issue will get resolved.