I've removed the link as strictly speaking you not permitted to post links until you reach minimum 15 posts.
Posting the link caused your message to get held up in moderation queue. Sorry for the delay and the link removal that but that's the rule.

It's a tricky question you pose and 50 minutes is a tight connection. However it does (just) meet Cathay Pacific MCT (Minimum Connection Time) unless it got changed recently. Normally these MCT's achievable, but there'll certainly be a push for you. If you have a family, say small children, it may be advisable to rethink the plan. With authorised MCT's CP will take full responsibility to organise and fund alternative flights in the case of any delays leading to missed connection etc. But they will not accept responsibility if the MCT is held/met but you failed to get to the departure gate in time.

I would strongly suggest to contact the airline to confirm the MCT and the details I've outlined. Better be safe than sorry and airlines often tweak there operational procedures.
When you check in you'll be checked through to final destination.

Be aware that Hong Kong is quite a big airport. Even short arrival delays will cut into that 50 minutes.
It's your personal choice given the facts.

It's happened to me twice travelling to Japan and luckily the connecting flight was held for us.
Probably because there was a significant number of us for that connection. But that scenario may not be true for your flight