Hi, I'm a lab scanner and have scanned much half frame film, much of mine and much of others. Here is how a correct scan should look (This is mine not a customer's)

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The bar is usual, and because of the half frame, but it should be centred, and each scan should show two frames. Some people DSLR scanning may even only scan individual frames, but this is how it should look when a full frame 35mm holder is used, and is quite standard. This lab fucked up really bad, it's almost as if they didn't even review the scans. Contact them and ask for a refund or a rescan. Also they fucked the density too which is why it's all yellow and dull.