OVERKILL
$100 Site Donor 2021
It's not a viscosity issue, and it's not an MDS issue. The early MDS HEMI's didn't have lifter failure, it wasn't until they introduced VCT, which involved some other valvetrain modifications, which I believe included updated lifters, that the issues started appearing. 2010/2011/2012 were "peak" years, but anything pre-2018 is susceptible, and I've heard anecdotes of the odd post-2018 experiencing it, but I've never seen one torn down to actually show the newer, updated lifters failing.The real issue came about when they integrated MDS. These lifters use oil controlled locking pins. They are much more intricate and have tighter clearances, and need a clean oil.
There are a ton of early MDS HEMI's still on the road, like my wife's '06 Charger R/T, that didn't have VCT. It's really quite interesting in terms of the whole manifestation of this issue and fingers being pointed at different things (oh, the lifters aren't being oiled! being a classic) when there wasn't a lot of root cause analysis being done. It was @Team Zero, who no longer posts on here, who is/was a dealer tech that shared the failure mechanism, including pictures of what fails, and why.