Nrf9160 DK does not send periodic TAU when no tx is due


in NB-IOT the UE should make a Traffic Area Update TAU when timer T3412 expires. I have a project based on the UDP_with _PSM sample. When I configure the PSM timer to be 1 minute and a data transmission every 10 minutes, it is my understanding that the UE should do the TAU every minute even if there is no data to transmit. However the UE only does a TAU after sending data every 10 minutes.

I have tried different settings for the defines below, but these are the current ones

#define CONFIG_LTE_PSM_REQ_RPTAU "10100001"
#define CONFIG_LTE_PSM_REQ_RAT "00100000"

DK version is 0.8.2, and I tried with ConnectSDK Tag v0.4.0 and v1.0.0. Modem firmware is 1.0.1

Any help would be appreciated.