Artex C406N - no Lat/Long position data on test set

Why can't my IFR 4000 or AVX-10K decode the LAT/LONG data when testing the Artex C406N ELT, while all other information is properly decoded?

Please refer to the following comment provided by the ELT Manufacturer- ARTEX The ELT C406-N https://www.acrartex.com/products/406-n/ does not store or acquire position information in the Arm/Off/Standby mode. It will only acquire position information once it live activates via the Switch/Remote Switch or G-switch. On the initial live activation the ELT will download the latest position information and update it as long as it is receiving the information and then transmit the first 406 MHz burst at 50 seconds with the identification hexadecimal code and position coordinates digitally encoded. The ELT will transmit the 406 MHz burst every 50 seconds after that with the latest postion data encoded. When performing the self-test it will not transmit any position data. This statement confirms that the position data, will only be encoded/included in a live distress message after 50 sec.