Market.deal occasionally fulfills amount-1 instead of amount
This may be a tricky one to replicate, but I have run Game.market.deal() with a round amount, e.g. 2000, but gotten a fulfillment of only 1999. So far I have only seen this happen when using an amount that is equal to the size of the deal. I suspect there may be machine rounding or other issues taking place that cause the final integer to get rounded/floored down by 1.
An example of an instance of this occurring was a transaction I made on tick 13559636 for 1999 H. I entered 2000 when calling Game.market.deal, but only 1999 was fulfilled.