Why are some Strange TF2 items showing as 'Restriction'?

It's because the TF2 schema changed in a way that looks like an error on Valve's part, causing the "friendly name" for the Strange quality to be "restriction" instead of "Strange":

"qualityNames": {
    "Normal": "Normal",
    "rarity1": "Genuine",
    "rarity2": "rarity2",
    "vintage": "Vintage",
    "rarity3": "rarity3",
    "rarity4": "Unusual",
    "Unique": "Unique",
    "community": "map",
    "developer": "Valve",
    "selfmade": "Self-Made",
    "customized": "Customized",
    "strange": "restriction",
    "completed": "Completed",
    "haunted": "Haunted",
    "collectors": "Collector's"
},

The line "strange": "restriction" used to read "strange": "Strange".

Any software that uses the TF2 schema as the authoritative source for item (including quality) information will suffer this same bug and label all Strange-quality items as "restriction" instead. (If only some are being labeled this way then the software might be caching the titles for some items, so those would be displaying correctly since their titles were put together from the raw item data before the schema change.)

Note the similar error for the community quality.

I have one system that refreshes the schema periodically, serving it up to my own software when they need the schema (to reduce bandwidth to Valve and generally be a good netizen) so I was able to fix the problem in my own software by disabling the automatic schema updating process and manually editing the schema to reflect the proper quality names.

Update 2015-06-01: The latest version of the schema no longer shows this problem, so the issue is resolved on Valve's side.

The "restriction" item has been modified with a Strange part that counts the killings of medics with a ready Übercharge, while the others are a "plain" version of the same item.

An item of this kind is worth more because the Strange parts aren't easy to obtain, since you can only get them from a crate with a very low drop chance.