IP Filter range not working

I use the Layer-2 IP filter function on a RB750 to test one way packet loss for RTP streams. I define a simple port range in a filter and either drop or accept on the forward chain. This works fine with version 6.27 on a RB750. When I upgraded to the latest version 6.4.9, it stopped matching the filter. I can change the filter from a port range to a single port number and it matches. Is this a bug or was the feature removed?

Thanks,
Md