[exim] Strange DISCARD problem

Using this line in my connect ACL:

discard    condition = ${if eq{$interface_address}{127.0.0.8}}

On some of my servers it works, on others I get:

H=[127.0.0.8] temporarily rejected connection in "connect" ACL

Other servers work fine. I can't tell the difference since they are all
running the same configuration. The only diffetence is that some are
running 64 bit exim (the ones that fail) and the ones that work are
running 32 bit exim.