Some Station scanner software issue likely too. Stadium MRT Station scanner will keep buzzing for quite some time before it finally successfully scan my phone. I don't experience this with other stations gantry.
Found the solution for my issue!
Setting - about phone - android version - Google play system update - restart
Mine was a July update, it got updated to Nov after I did above and all good now!
Edit:And I realise if stamina mode is on, it wouldn't work on DTL CCL gantries. All good if stamina mode off...