STLINK-V3 Mini UART doesn work from the edge connector

[VKrav.1]

Hi EveryOne!

I use a brand new ST-Link V3 Mini shield and would like to use its Virtual Com-Port feature with connection via its Edge connector. SWD works well but UART doesn't at all.

I use pin 1 & pin 11 for connection to UART but no result.

PS. If I use the same shield but use STDC14 connector cable and its 13&14 pins then UART works via these pins. What can be wrong with 1 & 11?

[DAlbe.3]

Interestingly, I have the opposite problem with the V3-MINIE.  I soldered a 2x5 0.100" pin header to the 2mm edge connector at the end of the board and the UART functionality works, but the SWD does not (even though the 0.100" pins show no DC resistance to their matching STDC14 pins).  Even stranger is that the Vcc (target voltage detection pin) only works (for SWD) when connected to the STDC14 pin even though the STLinkV3 correctly measures the voltage when connected to the 0.100" pin.  If I connect the same target points through the same dupont jumper wires to a breakout board that goes to the STDC14, everything works.

@st: would you please supply a schematic (or at least a partial schematic) for the V3-MINIE showing any components between the edge connector and the STDC14 pin header?  Of particular interest: are there any frequency-dependent components (L/C) between them?  Any other ideas as to why SWD might work from the STDC14 connector but not the edge connector?  (I'm connecting GND, Vcc, SWDIO->TMS, SWCLK->CLK, nRST).