Your slide is out of adjustment if you can see daylight along bottom.
We had a similar problems with our '13 Winnebago Aspect. Rear slide was adjusted (poorly) by a warranty dealer. Fixed the daylight gap visible along bottom but not CO problem. Turns out the Onan generator had a small gasket leak (fixed by Cummins/Onan service) and finally the tailpipe that attached to the generator muffler was also leaking CO (That part was installed buy Winn). Cummins dealer ended up putting muffler weld around the connection as U-clamp was not sealing the connection. Finally fixed everything....also installed GEN-turi exhaust but that didn't help as the CO leak was under the RV not at the exhaust tip.
Wife took RV to Winnebago dealer for warranty repairs last Fall.. Slides were supposedly adjusted. She just informed me that on her first dry camping night, the CO alarm woke her up. Generator fumes still seeping into rear bedroom slide so its off to a different Winnebago dealer for warranty work again. (I'm in AFG so can't help out which is a bit frustrating). We looked at the aftermarket Venturi exhaust stacks but generator warranty does not approve and there is nowhere to hang it off the Aspect. (End of rant)