I have a similar problem with my base neighborhood (doesn't affect the NH's downtown/shopping/etc. districts), after having installed the H&M pack...

Tim (aka the Slipperman)

I think I might have found another mod causing this problem besides the 'Pregnancy Wear Any Outfit' one, which I don't have. After I removed the Smonaff's Change Clothes Pie Menu Option hack in my game, The clothes racks on the shopping lots don't have the issues that they did anymore.

Judging from these two mods, I think that any pre-Seasons mod that handles how you change clothes in the game might cause these problems.

Tim (aka the Slipperman)

Does it take you straight to the Buy/Build mode on the lot as soon as your Sim arrives at the shop?  That is what's been happening with my game...I've posted about this problem in ash577's thread (see the thread entitled "sim can't buy clothes?)

Tim (aka the Slipperman)

I have similar problems as the original poster here.  When I send a Sim to a shop lot it goes straight to buy/build mode for the shop lot for some reason, and I have to quit back to the neighborhood to regain control of the Sim I sent down there.  (This doesn't happen with *all* my community lots, just the shops)
Beyond that, everything else in the game seems fine.

Tim (aka the Slipperman)