TTN Record Wrong Freq Plan

TTN recorded many of gateway in Thailand as wrong freq plan. The correct freq plan should be AS923, AS920-923 or AS923–925. Many of them appear as ,“frequency_plan”:“EU_863_870” even though we register on TTN gateway console as AS920. Delete the gateway and register again cannot help. Why TTN determine and choose EU_863_870 rather use what we define on gateway console page? Does it depend on the software or configuration on our Gateway?

Somsak