Some RJ45 ports are a tight fit and the end of the connector can be pushed hard against the back of the port. In most instances this is not a problem, but because of the way the EZ RJ45 system works, it is possible that this can physically affect conductor spacing causing shorting with PoE and possible RFI/EMI issues.
Our recommendation in these circumstances is to slightly modify the way the connector is crimped. Prepare the conductors as usual, insert the conductors into the connector and push home as far as possible in the normal way. Ensure that there is plenty of jacket inserted. Then, using a good side cutter, (our part number 450128, for instance) trim the conductors flush with the connector. Pull back the conductors very slightly so that the ends are concealed within the connector, then crimp as normal with the crimp tool.