nRF9151 DK (LACA A1A) - UICC failure, card responds on I/O but modem reports NO ATR

Question

Hello, I'm working on a prototype device based on the nRF9151 DK. 
 HW: nRF9151 DK, nRF9151 LACA A1A Tested with modem_shell sample app, NCS v3.4.0. 
 Symptom: on boot, "The modem reports a UICC failure. Is SIM installed?" / Network registration status: UICC fail. 
 Diagnostics: 
 
 AT%CSUS? --> 0 (physical UICC slot correctly selected) 
 AT+CFUN=4 --> +CFUN: 4 ; SIM_VCC on J5 C1 = 0 V (correct) 
 AT+CFUN=41 --> OK ; SIM_VCC pulses ~360 ms with retries 
 Oscilloscope at the socket during activation: CLK clean 1.818 MHz (varies 200 kHz-1.8 MHz across retries), RST 2-3 pulses ~100 ms, I/O shows clean digital data - the card IS responding 
 AT%XSIM? --> 0 
 AT+CPIN? --> ERROR 
 AT+CEER --> +CEER: "UICC 0"

Ruled out:

SIM card: 1NCE, Onomondo, Conexa - all identical NO ATR 
 Modem FW: mfw_nrf91x1 2.0.4, 2.0.3 - all identical 
 Config: AT%XFACTORYRESET=1 performed, no change; %CSUS=0

Modem drives VCC/CLK/RST correctly and the card responds on I/O (visible on scope at SIM socket and P28), but the modem never receives a valid ATR. 
 sim 1NCE, trace-2026-07-16T18-04-57.255Z.mtrace

Does this look like a hardware fault to you, or did I miss something? If it is hardware, I'd like to proceed with an RMA. 
 Regards, 
 David