128-bit UUID byte swap problem

[kerem]

I'm implementing a custom service with one characteristic and 128-bit UUID.

I am able to set the custom base UUID using sd_ble_uuid_vs_add() but the resulting bytes look swapped in nRF MCP Android application. This is on Softdevice 7.0.0 and SDK 6.1.0.

#define BASE_UUID {0xAB, 0xCD, .., 0x12, 0x34}

the resulting UUID I see is first and last 2 octets swapped, also within themselves like this;

{0x34, 0x12, .., 0xCD, 0xAB}

All the octets in between these 4 are fine.

Any idea what could cause this behavior?

EDIT Attaching screenshot from Android MCP:

[Hung Bui]

@kerem: What RK explained was correct. It was the encoding difference. In the code we use little endian but when displaying on MCP it was big endian. Could you try smth else not with 00 in the middle ?