The Shader Pack DLC
*should* have had an update made to the source file SP_Environment. That said, I have not bothered to update it(I did a quick test of it for the author in August so had no need to update), in general I don't use steam much and run AGKC/S without. I have just loaded the steam app...nothing appeared in my download manager though! So I just checked the installed files and dates and nothing since June(which to be fair is probably me making changes to the original instead of a copy by mistake). I have AppGameKit set to auto update but I see no setting for updates for DLC. Having also checked the installed version of SP_Environment shows that no automatic install took place as the updated version is not present in my install(I do have automatic updates set).
So baring that in mind i have just verified the files using steam itself. It did indeed update the SP_Environment source, however it was not with the updated version I tested but the same original version as was originally installed(17kb - the update I tested is 18kb), confirms basically it was my own alterations of the installed file by mistake instead of altering a copy.
I guess then it isn't this particular DLC?? The only other DLC I have are the freebies ie the games packs/education pack. Oddly I claimed all of them in recent months, yet the date "Added" column show them all as added back in 2020. So steam apparently considers "Added" as when added to steam as a product. So no obvious way of checking other than checking the dates each file was last modified. It also appears that only the last folder in a path gets a last modified date, so manually checking most paths and filtering to show by modified date as the priority is the only way to go for certain.
Given I just verified AGKC files and some activity occurred in the steam DL manager, I was expecting to see today's date in the Update section...nope it still says January 29 2023!!! So in essence there is no way of telling when anything was last changed with AppGameKit itself or the DLC unless an official update took place. Or have I missed a trick here and there is indeed a way to check dates for anything other than the authors publication date?
Have you by chance selected things at some point to add like the free DLC(or purchased), perhaps not given it chance to to DL and install fully, closed the steam app then forgotten about it and only booted steam app recently? Assuming both AppGameKit and the DLC dates of installation are not given, is it a possibility?
Win 10 Home 64, Intel(R) Core(TM) i5-10300H, 8GB DDR4, NVidia GeForce GTX 1650 4GB GDDR6