There is a gap in the seal under the slide for the slide extension track. The generator exhaust isn't far from the gap. You may have been getting CO from the generator through it.
If fans are all that you need, instead of running the 33 amp generator to supply 1 or 2 amps to fans, get a cheap inverter or two, plug them into your 12 volt sockets, and run the fans off your coach batteries. The batteries will run a few fans for days. Just run the generator as you need to recharge the batteries. If you run the A/C a few hours during the day, the generator run time should be enough to recharge the batteries for the fan and lights usage. Check the wattage on your fans to get the right size inverter. One inverter could run two fans even if you need an extension cord to reach to one fan. Of course, you could install a permanently mounted invertor.
If you must run the generator while sleeping, pull the slide in. It seals much better when in.
You could take a look at generator exhaust extensions that are sold by RV supply places.