I have switched to HTTP Switchboard, works pretty well. https://chrome.google.com/webstore/detail/http-switchboard/m...
Edit: To clarify, the above is in comparison to HTTPSB.
Workaround is to un-block whatever net requests which are causing a site to break. I can't make sense of "no work-around": unblock everything?
Edit: There is a scope-based switch to completely turn off matrix filtering.
I was referring to a few issues I encounter in uMatrix which are not present in HTTPSB. I probably should log them; was not sure if uMatrix is ready for full-time use yet.