Warranty does not cover damages in storage. It only covers faults of manufacturing and material.
There is no need to be concerned. Your camera and lenses are designed to work in these conditions, check your manual.
Is RH of 30-35% really too low? AC in office buildings is typically not switched on 24/7 anyway. Besides, the camera shops store their stock in their air-con shops with no trouble. Don't think their shops or storerooms are humidity-controlled.
So what? Ever heard of lens damage due to RH fluctuating between 35% and something higher? Those cameras in museums, 100 years older or more .. those might be sensitive to fluctuating environment conditions ...
I am just curious. You sure your office RH is that low? Typical air con commercial bldg should be at least 50% and above. If you are using DX or VRV system and running 24/7 then it is a case of not enough fresh air.
Your office RH is way too low if you have used a digital RH meter it's sometimes off by 5-10 so it may be 45-55 actually which is a typical office RH. Even a Datacenter RH is maintained at 50% so your office cant be that low.
Having dry cabinet shouldn't be a problem you can control the RH in your dry cabinet your office you may not know after office when they shut down the AC the RH may raise or during weekend when there's no AC.