Fixed Dialling Numbers are not calling unless I disable then enable

We have multiple amounts of the Samsung XCover 6 Pro devices in circulation.

We are experiencing issues where the fixed dialling numbers will not call after the phone has been power cycled.

The only way to fix this is to disable the FDN and then re-enable FDN where it will call all the allowed numbers, but once we power cycle the phone again the FDN is preventing any call including numbers on the FDN list.