SDL Trados Studio 2017 has bugs with 不良 and 類 as it cannot search and suggest translation for these terms (不良 and 類).
Therefore, if a sentence (translation segment) has one of these terms, no translation options will be shown not only for 不良 and 類 but for other terms in the sentence as well.
Bug of 不良:
"Searching for terms" in Term Regconition panel forever:
Same with 類:
Here's the list of Japanese terms unable or difficult to search in Trados 2017:
List of unfavorable Japanese terms in Trados 2017
不良 × (unable to search)... and counting. (See full list below)
類 × (unable to search)
良好 △ (difficult to search)
種類 △ (difficult to search)
衣類 △ (difficult to search)
Terms like 良好, 種類, 衣類 are only difficult to search, to add to termbase, etc. but you still can deal with them, so they still work in Trados (no need to fix them). I listed them here just for reference purpose in the future.