Dell AMD R5 430 GPU part #931Y4F. Not possible to activate 3 displays

Can anyone verify function of 3 displays on this specific Dell graphics card?

TLDR;  Though DisplayPort 1.2 MST (daisy chain function) works on either port for 2 monitor function.  Activating a 3rd DisplayPort monitor direct connected to the other DP header will not activate via Windows display settings.

Long version;

We're considering buying new SFF Optiplexes for our 3 monitor setups.  I noticed most of the SFF Optiplex we've been looking at (3060, 5060, 5070, 7070, XE3) offer the Dell 931Y4F AMD Radeon R5 430 video board as a beefier graphics option. Our existing units (HP Workstation Win10 x64 with Intel P4600 graphics) could benefit from a beefier graphics board anyways so I went ahead and bought the Dell card here 

https://www.dell.com/en-us/work/shop/amd-radeon-r5-430-2gb-half-height-dp-dpcustomer-install/apd/490-bemx/graphic-video-cards

The workstation booted up no problem and Windows update loaded the April 2019 AMD driver.  Doing 3 monitors off a dual head GPU such as this requires that one of the monitors run off the Displayport 1.2 daisy chain.  That is how this workstation was previously functioning no problem with 3 monitors on the Intel graphics.  Two Dell U2413 were running off a single Intel Displayport 1.2 header via DP MST.

The (2) Dell U2413 monitors (we’ll call them A & B) operating via DP MST daisy chain work fine.  The 3rd monitor (we’ll call it C) connected to the alternate DP header presents in device manager and under the Windows display control panel.  I expected I would just have to activate C via “extend desktop onto this display”.  Yet, making that selection fails to activate display C despite the 15 second countdown to keep the settings.

Now the weird part.  If I disable either one of the daisy chained monitors A or B the 3rd monitor C on the alternate DP header activates instantly and functions fine. I can disable the first monitor A in the DP MST daisy chain and leave active the second daisy chained display B and activate the 3rd display C on the alternate DP header and that combination works fine.

I’m convinced Displayport MST daisy chain is not the issue but rather something most likely at the driver/firmware/chip level for this specific Dell AMD GPU. I’ve tried the more recent drivers direct from AMD 19.12.2 & 20.1.1. The ill behavior persists.

Though I don’t think logical given the behavior, I even swapped out the cables, monitors and swapped around the connections to the Displayport headers on the GPU. The cables are the full-size DP 1.2 cables that came with the monitors. Though the monitors support it, I don’t have any cables with DP mini connects.  I’m not using any adapters…just straight through cables.

I even tried running the daisy chain off of monitor C (an LG that supports DP 1.2 MST as well) and all three work but only when two at a time. Swapping from the 2 AMD Displayport headers back to the two Intel Integrated DP headers activates all three simultaneously just as functioned before attempting the AMD GPU.

On the chance that allowing the integrated GPU to be activated was somehow impeding, I also tested with that disabled in BIOS. No luck. I don't think it's a bandwidth problem because it shows up exactly how it's supposed to as PCIe 3.0 x8 link. Also a 4k display works fine. I checked to see if Dell offers an OEM Nvidia 1030 card but I don't think that's the case.