Yup, appears to be a classic case of low tongue weight.
Just looked at the pics/floorplan/specs for the 27FS. First off, I can't believe they designed this thing with an empty tongue weight of just 830 lbs. . . . WITH A REAR GARAGE!!! Please tell me I'm missing something here?! When you load your toys in the rear garage area this minimal amount of tongue weight can only go lower! The garage appears to be located almost entirely behind the rear axles. There's no way to move your toys over, or in front of, the axles to increase tongue weight. You're only option is to load EVERYTHING loose inside your toy hauler (gear, food, etc.) to the very front (preferably in the front bedroom), and significantly fill your forward tanks. They should have designed this thing with the axles positioned farther back, underneath the garage more.
Anywhoser, been there , done that. I will not buy a toy hauler unless it has a completely open garage area directly over the axles. I want the option to load nothing or everything and have complete control over my tongue weight.
IMO, a lot of folks seriously underestimate the loaded weight and the **potential** tongue weight of these toy haulers when loaded. Due to luck, most get away with it. I own the smallest Ultra Work & Play toy hauler (18ft cab, 22 ft overall). Unloaded weight (using nearby scales) is 5,000 lbs. Forest River advertises the empty tongue weight to be ~770 lbs. After loading my 11ft. jetski & trailer, gear, water (partial fill), and food, it hovers vacation ready at approx. 7,000 lbs. (again using nearby scales). Fully loaded, with my black/grey tanks empty, I can keep my tongue weight just below 1,000 lbs., which is optimum (14-15%) for my tastes. FWIW, if I take a couple of showers on the road (partial fill of my grey tank) my tongue weight increases to ~1100 lbs. The max payload on my 2012 Tundra is 1,500 lbs. Try very hard to put absolutely nothing in the truck (in the bed or in the cab)--put everything in the toy hauler. Got plenty of tow capability (over 10,000 lbs.), but I'm acutely aware that I have very little payload capacity (true for all 1/2 ton trucks). I also make sure to keep the tongue weight balanced between the front/rear axles of my Tundra with a properly adjusted WD hitch. The result of all this planning? It tows like a dream! I cannot make it sway no matter the wind or how aggressively I drive.