I see two issues with the new configuration. First, if that is a XPF filter between your CM15A and your transfer switch, that will block the X10 signal from reaching the distribution panel.
Second, it looks like you substantially increased the wire length between the CM15A and your new distribution panel. As you know, X10 signals decrease in amplitude as they propagate away from the transmitter. Even if there is no XPF blocking the signal on the CM15A circuit, the additional wire length will reduce the signal strength even more. The new distribution panel will be a major load on any remaining signal, and the signal strength has probably dropped into the noise level by the time it reaches the XTB-IIR.
If you have a XPF in the CM15A circuit, you certainly should remove that. Then if the CM15A signal strength is still too weak, you could try moving the XTB-IIR onto the CM15A circuit to pick up its direct feed. That may be possible at the old distribution panel if you have both phases there.
Jeff