Items not building in shop

I just had a game where my Vampiric Sceptre wasn't built into The Bloodthirster when I purchased the item.

I had Vampiric Sceptre when I returned to shop, and when I bought The Bloodthirster my Vampiric Sceptre wasn't utilized, and I ended up with both items instead.

Of course my dumb ass didn't notice until I left platform, so it ended up costing me the 900 Gold for an extra sceptre plus the difference in sell value when I scrapped it.

I don't know if it's other items, but this was the example I just faced. Is anyone else having troubles with items not building into the next tier?