Searches in which a letter contacts a non-letter cause search descriptions to be hidden. This appears to be entirely a client side issue as the http request made still returns proper results for all searches.
The searches below are exactly the same however the first search contains a 6 contacting a letter. This only occurs when a number or symbol contacts a letter.
https://developer.roblox.com/en-us/search#stq=test%20a6
https://developer.roblox.com/en-us/search#stq=test%20a%206
https://developer.roblox.com/en-us/search#stq=test%20a