BFGMiner is using some strict coinbase checks which results in "Pool misbehaving" errors for some particular coins on some particular pools, set by buyers orders.
make sure your're using the latest BFGMiner
you should add #xnsub and #skipcbcheck parameters to connection address:
example for Scrypt:
stratum+tcp://stratum.westhash.com:3333/#xnsub#skipcbcheck
example for SHA256:
stratum+tcp://stratum.westhash.com:3334/#xnsub#skipcbcheck