This behavior is expected. The valid combinations of BRI Voice Interface Cards (VICs) and voice network module hardware are:
VIC2-2BRI-NT/TE with NM-HD-1V, NM-HD-2V, NM-HD-2VE, and NM-HDV2
VIC-2BRI-NT/TE or VIC-2BRI-ST-TE with NM-2V
The only combination of hardware which is currently supported for the Cisco CallManager Cisco Media Gateway Control Protocol (MGCP) BRI backhaul feature is VIC-2BRI-NT/TE or VIC-2BRI-ST-TE with NM-2V. Any other combination of Network Modules (NMs) and VICs is unsupported, and does not function. The only workaround is to use the correct combination of hardware.
The MGCP backhaul feature is currently supported in Cisco IOS Software version 12.3(2)T and later, only on the original host network modules and BRI VICs. The MGCP backhaul feature is not supported on any C5510 DSP-based BRI modules in 12.4(2T).