I'm afraid that it points to an issue within the Filtering service and I don't know of a work around. However, by collecting logs and sending them in, you can help us take a closer look at this. The diagnostic logs can help determine where exactly the issue lies and, in turn, what can be done about it.
I have asked an excellent member of our Email team to send you instructions for collecting and sending logs. Once we receive those, we can take a closer look at this app conflict and figure out what to do next. In the meantime, if I hear something about Covenant Eyes and Spark, I'll update this thread.