Precision 7550s suddenly stop liking their memory (blink codes)

This is a strange one.  In the last week or so (it's May 2023), I have had three Precision 7550s laptops suddenly stop booting with 2 amber/5 white error blink code (memory issue).  Through trial and error, I have figured out that it I swap the bottom 2 memory modules (i.e. just switch their slots) the issue goes away.  If I swap the modules back to their original slots, then the issue comes back. All three systems have been working fine since the day I set them up with this exact memory configuration and the issue just came out of nowhere in the last week.  I have not added or changed any of the memory on these systems in over a year and a half.  

These systems have 4 slots in total, so two on top below keyboard and two on bottom.  All 4 slots are populated with the same memory modules, so 4x16GB Non-ECC SODIMMs DDR4-3200 for a total of 64GB of RAM.  If one or two systems had this issue, then I could maybe chalk it up to a fluke.  Having three systems in a week with the exact same problem seems suspicious to me like something else on these systems is causing it (maybe the BIOS?).

All three systems are running different Bios versions with one on ver 1.21.0, one on 1.11.1, and one on 1.7.0, so that makes me think it can't be the bios.  They have different versions of the Intel Core i7-108xxH processors, but outside of that they are pretty much identical systems.  I am not looking for an answer to solve the problem, I am only reporting this observation in case others have run into the same issue and/or in the event there is something larger going here as it is very odd.