BC660K spends a long time listening if AT+CPSMS = "00110100","00000101"

Hi There
We have a BC660K design which was always working just fine.
The device is BC660KGLAAR01A05_01.203.01.203

Recently, I’ve start retesting supply current for 1, 4, 8, 12, 18, 24 hours between calls.
All was fine for the 1 - 12 hour times, but 18 hours has an issue which I am still tracking down.
What I have noticed is the current sits at about 25-30 mA for about 13 minutes after the unit should have gone into low power mode. Its not constant, but pluses a mix of slow and fast rhythms. I am guessing its receiving and doing something as there aren’t any 300mA pulses.
Any clues as to what this might be?

I recommend that you grab debug log for analysis
Quectel_EPAT操作指导与参考(CN&EN)_BC260Y&BC660K&BC28F&BC95GF&BC300Y&BC950K&BC280E&BC95GE.pdf (2.1 MB)
and I have sent the EPAT to you

Quectel_For BC660K&BC950K Development and Application Process in Power-off and PSM Mode.pdf (1.8 MB)