By the way, does anyone else have issues with vegetation not shadowing properly? The severity of the issue depends on the way your preset is set up, but it's pretty major for me now, so I thought about fixing it, see here:
Also notice the hanging moss shadowing partially on the left side.
Worth the time?
Same reason the doors were not shadowing. Since you fixed the door in Solitude you could guess why.
Anyway, nothing with alpha blending enabled can receive/cast shadows. I found that carrots have alpha blending for some reason, when testing shadowing/adaptation/skylighting around the back of Jorrvaskr. I just submitted the carrot fix to USKP as well as the Solitude door fix, which is how I found out about this topic (from the person who reported the bug).
If you notice anything not shadowing you're likely going to have to make sure the mesh has Alpha Blending disabled.
It's very expensive to do alpha blend / transparency sorting so they are usually removed from any kind of depth buffer effects like shadows.
Edit: Other reasons can be too strong Rim/Back lighting. If you have SMIM for example, the tomatoes appear to not be shadowed. They are, but he has rim lighting and backlighting shaders on them. They're a bit too strong looking in dark shadows.
Edit2: Also, I noticed you mentioned market stalls too. I realized that even though I submitted this fix last month, it was accidentally left out of the release of USKP 1.2.6 (it's marked as RESOLVED/FIXED)... So it should be making it into 1.2.7 along with the Solitude door fix; only one door was fixed in 1.2.6 .. the door is in two folders. Anybody who plays this game should be (better be) running the USKP... just if too many fixes start being included in this package without also including the USKP fixes, that's where the real problem with overlap occurs.