On a lighter side, water in the bilge after a rain storm is much less of a problem than water in the bilge when it hasn't rained
I am not familiar with the construction of the 285 so my comments are somewhat generic.
Some water may be expected. The real question is how often the bilge pump gets activated. If for example, during heavy rain, the bilge pumps runs every 30 seconds, you have an issue that needs to be looked at.
On the other hand, maybe there is a bit of standing water in the bilge that isn't deep enough to trigger the pump.
Unless you are there to watch the bilge through hull, it isn't easy to know how serious the problem may be. There are some electrical counters that can be wired to the pump(s) and count how often they run.
Hopefully someone with direct experience on that model will chime in.
So in the best case, no big deal. In the worst case since the boat is new, something wasn't sealed or plumber correctly.
Keep us informed.