Bunch of buyers randomly piling in after my offer?

I made an offer on a house that was sitting on the market for +40 days and had a price cut of $35k. Right before I made my offer I called my agent to go over my offer and she let me know that just 15 minutes before I called someone made a cash offer, but it is lower than what the seller is looking for. I thought that was pretty interesting considering how many days the house was in the market with no offers.

My offer expires at 4pm today and at noon I called my agent again to see if there were any updates and she let me know that the seller is expecting ANOTHER offer in the next couple hours, but I am currently beating the cash offer. I let her know that I will not be increasing my offer and if the last offer comes in higher the other person can have the house.

Is this normal? Why all of a sudden the flood of interest?