Got a one cab 500 system. MCP 2 ( red )
Latest software V 2.76 on Smart media card.
Using OSM V 3.76
Connect to system, MMC 722.
Some phones show me no buttons programmed, while others show up properly. Yet checking from the affected phones, they are in fact programmed.

Any solutions ?

TIA
Max

What if you check over MMC programming on the phone?

Make sure you have the correct sub version.
I have 3.76b for OS500 OSM.