We've noticed occasionally a bit of odor from the tanks in the bathroom while we're using the trailer. (Which, for what it's worth, is basically the same as the 8329SS.) Finally, last weekend I was getting ready to take a shower and my wife had just finished doing the dishes. She pulled the plug on a fairly full sink and in about 15 seconds the shower burped up its P-trap and the familiar odor showed up.
I just got around to investigating the vent as I thought it might be plugged. What it turns out is that the factory uses a sweep 90 with a deflector in it in the vent vertical pipe so they can drain the kitchen sink into said vent.
The deflector takes up a bit more than 50% of the area of the vent pipe. So, when you drain a lot of water from the sink all at once it can obstruct the vent and pressurize the grey tank causing the shower to burp.
It all seems assembled as intended and it doesn't leak, so it's not really a warranty issue.
Guess we just need to try to drain the sink a little slower to avoid the dreaded burp.
Current vehicle list: 16 Flagstaff 832IKBS, 14 RAM 1500 4x4 Hemi 3.92 Bilsteins!, 04 Dodge Ram SRT-10 40,000 miles, 03 Dodge Stratus Coupe R/T 225,000 miles, 97 F150 4x4 5.4L 235,000 miles, 80 Firebird Esprit (drag only), 78 Harley Davidson FX 79,000 miles dad bought new, 71 El Camino ZZ3 TH400 12-Bolt, 37 Ford 3 window 502 Chevy dad built