Is it normal for my support posts to have a little sway before the framing is finished?

The movement you're feeling is likely because you've relied on the **shear strength** of those lag bolts rather than letting gravity do the heavy lifting. When you bolt a rim joist or a beam to the side of a post, every pound of weight on that deck is trying to snap those bolts or pull them thru the wood. Over time, the wood fibers around those bolts compress, which leads to that wobble or give you noticed. It might feel okay now, but it's a mechanical failure waiting to happen. On a deck that high, especially one near a pool where you'll have people moving around and water splashing, you really want your beams sitting directly on top of the posts. You can either notch the 6x6 posts so the beam has a solid ledge to sit on, or use heavy-duty post-to-beam connectors. Right now, your fasteners are the only thing keeping the deck from sliding down the posts. Lag bolts are beefy, but they aren't meant to be the primary structural support for the entire weight of the frame and the occupants.

And don't expect the joists and top boards to just magically firm up the lateral movement. If the posts are tall, you need **diagonal bracing**. You should have 2x4 or 2x6 braces running at 45-degree angles from the posts to the beams. This creates triangles in your structure, and triangles are what actually stop that swaying feeling. Without them, you’re basially standing on a giant table with shaky legs. Since you're working in red clay and sand, make sure those concrete footings are deep enugh to hit stable soil. If the footings are shifting even a tiny bit in that sandy mix, that movement will telegraph all the way up to the top. I’d seriously consider retrofitting some notched supports or adding additional posts directly under your main beams before you get it fully loaded. The weight of water and a crowd of people is significantly more force than a few boxes of Deck Mates can handle.

Deck Mates are fine for the 5/4 decking, but they aren't structural. If you’re still feeling sway, swap those lag bolts for GRK RSS structural screws or TimberLoks. Lags lose tension as the PT wood dries and shrinks, wich is likely causing that wobble.

Grab some Simpson Strong-Tie DTT2Z tension ties to lock the frame. Also, you need mid-span blocking between those joists every 4 feet. Without it, your 2x10s will twist like pretzels once the humidity hits that red clay. I never build a pool deck without solid blocking; it’s the only way to kill that 'trampoline' feel when people are jumping in.

One thing people often overlook is the specific fastener schedule for your joist hangers, particularly if you're using galvanized common nails versus the proper structural connector screws, as the difference in withdrawal resistance becomes paramount when you factor in the inevitable moisture-driven expansion and contraction cycles that occur so close to a pool. If you've just used standard deck screws for your hangers, the lack of shank diameter will eventually lead to fatigue failure under the rhythmic oscillation of people climbing in and out, so ensuring your hardware is rated for that specific shear load is non-negotiable for long-term safety.

Seen it a hundred times. You're finding out why we used to use 1/2-inch carriage bolts all the way through the post with a big washer on the back. Lags are easy, but they don't clamp the wood togehter like a through-bolt does.

Since you're in that red clay, did you flare out the bottom of those holes? If you just dug straight cylinders, that clay is going to turn into grease the first time the kids splash water over the side. Those footers will start wandering and you'll be leveling that deck every spring for the next decade.