That article seems to raise a few other questions too!
It also spread to a business in Manila, where WHO is a major customer but whose staff are employed by Playtech.
Mighty generous of Playtech to employ, and pay for, staff for another company
Playtech officially "do not have offices in Manila, and never have done......". They elaborated this by saying that any connection to Manila is down to individual casino operators having their operations based there.
There is evidence, some from their company reports, that they LIED when making this statement, and now the Telegraph raises the possibilty that this disruption has been the work of Playtech founder Mr Sagi, who could put an end to it with "just one phone call".
The manager who resigned is alleged to have said he was only there to "protect Mr Sagi's interests", which seems to suggest he was a "plant" in the Tel Aviv operation, possibly with an agenda of his own, and not one necessarily in the interests of the major stakeholder in the operation, William Hill.
The earlier falling out between WH and Playtech could be what has lead up to this, with allegations that the senior manager didn't just resign, but tried to poach all the staff and had them sabotage the computer systems. He had taken exception to the demand from WHO head office that he open the computer systems to them for "day to day" access as part of a detailed internal auditing process.
If the Manila walkout is from the business I think it is, other Playtech casinos will be feeling the impact, although they may have taken better measures than WHO to ensure none of their players notices.