Did you suspect is was fraudulent when you received it, or were you totally taken off guard??

I always buy insurance to guard against exactly what you wrote about. 

Is there any common mistakes made by new agents that I should be on guard for?

If its an older hvac unit outside you may build a decorative lattice guard around it to hide it, paint it too.

Engineers stay after hours to do other jobs like guards, mow grass on company property,  etc etc.. 

I'm in the National Guard myself and also a newbie.

If you're able to raise rents up to close to market level (and market rent for a place like this is DEFINITELY information you'll need to lock down a lot closer than you currently have it, because it's crucial info to not only the profitability* but also the value of the property), AND you have cash reserves to guard against the run of bad luck, I would consider doing the deal.

One last thing: don't be in such a hurry to find a tenant that you let your guard down and end up with a really terrible one.

Your deal needs to be based on a bit of trust, what your seller needs to see is your ability to cover the payment as well as your motivation and commitment to do so to make them warm and fuzzy.Tell you seller, there are no guarantees in life, there is no guarantee the lender won't call the loan due, none that he won't drop dead and that heirs won't encumber title, or that the place won't be destroyed and that you'll receive insurance proceeds to build a new home, lots of things can go wrong, but the best guard against these matters is by using a loan servicer. :) Jon, Jon, Jon.....

Of course, i havent signed anything yet because i was caught off guard by this, but is this normal?