I don’t know exactly when the issue started for me, so I don’t know which backup precedes it.
However, I notice now that not only have a bunch of Qobuz versions updated to implausible dates, they also are shown as versions that are separate from the existing primary local albums in my library. There are quite a few of those and it’s quite a mess!
For instance, this album is suddenly a separate one, and I suppose I always had this in my Qobuz library, but I added it years ago. Now it has an added date from Qobuz of December 24, 2025, which is definitely wrong (I was not even at home over Christmas!):
While this is the local version that I ripped and added on Dec 31, 2020:
I am pretty sure that these were previously grouped, and now they are not. It’s not even recognized as a version of the same album. I any case, I definitely did not add this from Qobuz on December 24, 2025
In quite a few other cases, they are recognized as versions, but ungrouped (note the “Group All” top right):
Again, I am quite sure that my local copy (added date January 17, 2021) was the primary version. And the Qobuz version is now also added with date December 24, 2025, which is definitely wrong.
This one has no local version but I definitely added it from Qobuz years ago, not on January 19, 2026:
It seems that there is a particularly large number with an incorrect new Qobuz add date of December 24, 2025. Some have later dates, the latest ones being January 19, 2026, and going back in time I find some incorrect dates added going back to at least September 2025, maybe longer. I note that those are not new versions and they have all my Roon metadata of play counts, tags, but I definitely didn’t add them in e.g. September 2025 but years earlier.
The further I go back, the more unsure I am about many albums, of course. Though I do think that this stops at some point in the 2025 dates.
NOTE: If you go look at my logs, be aware that I have just cleaned up the above examples and more that I had now found as being ungrouped from their local versions with too-new Qobuz added dates. I could not bear the disorder 
EDIT: I had a separate issue with the Jens Friebe album from above. Mentioning it on the off chance that it’s related:
The Qobuz version of the album (that I added years ago) was set to “hidden” in my library, IIRC because it was always shown as a separate cover, even though I always have “Show hidden tracks and albums” set to NO. Probably some weird metadata issue.
Now that the Qobuz version has the incorrect new date added, though, this newly added version was visible, again separately from the local copy.
I selected both and clicked “Group alternate versions”, but this had the strange effect that ONLY my local copy was visible and there was no VERSIONS tab for the Qobuz or Tidal versions of the album. This confused me, but now I guess I understand that the cause was that the actual Qobuz version in my library had still been hidden.
I could fix this by 1. setting “Show hidden tracks and albums” temporarily to YES, then unhiding the Qobuz version, then setting “Show hidden tracks and albums” back to NO. Now it works ok again, insofar as they are grouped and the primary local copy has the VERSIONS tab again, with the Qobuz and Tidal versions in there. However, the Qobuz version still shows the incorrect date added as December 24, 2025.