I have some mappings that have the Accelerated Polling option enabled, and they no longer seem to be working. The "Streaming poll found n changes" messages that I used to see in my logs aren't present anymore. Data sync from periodic polling at my mapping's polling frequency is still working.
A workaround to get the accelerated polls and streaming updates working again is to re-authorize your Salesforce connection with Heroku Connect.
We are investigating the underlying cause of the problem.