why nrf52 devkit BSP button long press action doesn't work after BLE connection establishes?

Hello, I am using SDK15.2 on nrf52 DK with SD 6.1.0 and having an issue in long button press action. The single press and long press button action work ok before BLE connection establishes between DK and android device. But once the connection established, only the single press action works. I think this issue could be because of the app_timer used by the button and is disturbed by some other routines. But I am unable to find any solution.