They are owed something by the company and the judge ruled that they should be compensated – do they have to pay zakaah on it?

Zakaah is not due on this money until one year has passed
since you acquired it, because one of the conditions of zakaah being
obligatory is that the wealth should be in one’s full possession, and full
possession of this money was not achieved until after you received it;
before you received it, possession was not established, you might have
received it and you might not have, based on the judge’s decision and
whether the company was willing to pay. 

The scholars of the Standing Committee were asked about a
case where the government delayed paying money to those who were entitled to
it for nine years – do they have to pay zakaah on it? 

They replied: 

If the matter is as described, they should wait for one year
starting from the date when they receive it, then they should pay zakaah on
it. There is no zakaah due for the past because they did not have full
possession of it. End quote. 

Fataawa al-Lajnah al-Daa’imah
(9/284). 

And Allaah knows
best.