This isn’t really a bug (per the RFCs), but was causing problematic issues.
Parsing “MAIL FROM: <address>” was failing due to the added space in there. I tried making the parsing strict to the RFC, but for some reason the perl5-porters mailing list tripped up all over this one. I don’t really know why (I’ll ask Ask Bjorn Hansen some time).
It didn’t cause Haraka to crash – just emit: 501 Error parsing command.
Fixed, and pushed to github.