Am willing to experiment, but will have to make an effort to find a pool, as all my training work (pool or open water) is @3hr drive form home.
Yes, Don as you say the camera itself, using the on board flash seems to be working ok, on land, at depths to 100', which is max depth it's been to. Strobe has no failures above water, but while I have preformed none of Sabbath's gradual depth testing, it has failed to flash in sync with the camera at any depth I have tried, say @30-35' to 65-70'. Sea Life replace the pick up for the flash link couple years back, in an upgrade, but that did not solve the problem like we all expected.
Have even tried underwater to double check pick up, to ensure the alignment of link under rubber boot is correct on the pick up on strobe head itself. Also have tried to de select and then re select remote flash command setting, etc, while diving, to see if that got results. Nada.
SealifeJoe in a PM suggested a possible crack in flash link itself, but no test suggestion for that. That was why I added the extra step to test/update #19, and aimed the flash of the camera at the end of the link. To see if it triggered the strobe in sync, which it did.