Same here, did 3 dives without problem, the fourth dive just filled with water.

As a product designer, I would say this is not a good design, the diameter of the O-ring is way smaller than the recessed trough, this means the O-ring will comes out easily without notice. You may pinched the gasket and damaged it. This O-ring design will need some improvement!!!

There're few little retainning ribs for the screw ring, using normal force, you may think it's tightened enough but you may have not passed over the ribs yet. You will need a bit more substantial force to do this. To re-sit the O-ring properly  you will need to push the screw ring out and must remember to screw it back with more force overpassing the retaining ribs.

The gasket interfacing flat surface on the main body have over sprayed black body paint on the 3 and 9 o'clock position gives me a huge concern of water tightness.

The worst thing now is a dead osmo pocket and no more video recording for the remainder of the trip!

Hello and good day. I am sorry to read and to know what happened to your DJI Osmo Pocket. This is not the experience we want you to have with your DJI Osmo Pocket and with DJI.  Since this unfortunate event happened. I would recommend you contact our support team at https://www.dji.com/support?site=brandsite&from=nav for us to be able to assist you further. In addition I will cascade these information and this thread to the designated DJI department for further evaluation of the DJI Osmo Pocket waterproof case. Again I am very sorry for the trouble and thank you for the information you have shared with us today.

DJI Stephen Posted at 3-15 12:36
Hello and good day. I am sorry to read and to know what happened to your DJI Osmo Pocket. This is not the experience we want you to have with your DJI Osmo Pocket and with DJI.  Since this unfortunate event happened. I would recommend you contact our support team at https://www.dji.com/support?site=brandsite&from=nav for us to be able to assist you further. In addition I will cascade these information and this thread to the designated DJI department for further evaluation of the DJI Osmo Pocket waterproof case. Again I am very sorry for the trouble and thank you for the information you have shared with us today.

I hope the flight back to Canada will be on schedule under the current covid 19 situation. My only miss is the ability to take good video without the osmo pocket and can only use my cellphone at the moment.  I bought all the accessories.... and a bit upset not being able to use it.....

Same happened to mine today!

Six or more dives with no problems or leaks then today set up all the same way and after forty minutes the device had gone off. On returning home there was about a teaspoon of water in the bottom and the osmo pocket is goosed!

Really, really annoying. Set up the same way at home each time before heading out to snorkel then tested again before entering the water and despite that it leaks this time and that’s it fried and useless.

I got some Pretty good footage and had lots of questions and comments from customers about my videos on my Facebook and Instagram business pages about what equipment I use but this is very disappointing. Had I known of the number of issues I’d have got a GoPro

Found the perfect O Ring! I wonder the product mostly had designed with this O-Ring!!!!!
With this O-Ring, I'll be very confident to dive with it again for sure!

Dynaline 54141 3/32" ID 2-5/16" OD 2-1/2"   Or
Standard O Ring size 141, use A70 hardness or softer.