Cryptic crossword clue
By sound of it, notices working partner at certain times only 10

The most common and most likely answer to this crossword clue is the 10 letter word SEASONALLY

I've seen this crossword clue in Financial Times
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Buddy explains!

The straight part
We know that "at certain times only" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case at certain times only = seasonally.
The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.
This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.

What does SEASONALLY mean?

SEASONALLY adverb
  1. Occurring every season.
  2. Occurring only in season.

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