It's a known bug. Do not fear all your replay still exists, they're just not chown. Eventually if you have pastat mod installed, you can get your replay ID from it and directly click on the link to see the replay.
Yeah, wanted to report a bug & therefor add a link to the gameplay video where you can watch it, but i wasnt able to find the appropriate replay in the list of all replays & as said above, when i only wanted to filter for my own replays i had no results at all. anyway, the problem i wanted to report: my friend & me played in team 1 with shared units against team 2 with 2 AIs & against team 3 with 2 AIs. the bug happened right at the beginning of the game! one of the commanders from the AI spawned in a sea on an earth planet. a metal spot was so near to him, that he immediately began to build a metal building. after he finished it, he never moved again for the whole game which was about over a hour! the planet system was a custom one i created before the new patch, perhaps thats the reason for the problem? nevertheless, the next game we play, we repudiate water planets until the next patch is out where this is hopefully fixed...
I also ran into this in the Galactic War. A Faction Leader spawned on a water planet on Relentless difficulty and.... made a shipyard or two, a few power plants and mexes, and then sat there just building a modest fleet of ships, not expanding at all. The only reaction I got out of them was when I finally attacked, their commander trudged onto land and started building more stuff, shortly before his death.