> Maybe someone can predict the odds of this happening by chance as we dont see overlapping ORFs this long in humans?

There are 4^3 = 64 codons, three of which are stop codons. So p = 3/64 chance any given codon is a stop. The chance two in a row will *not* be a stop is then (1 - p)^2, for three it is (1 - p)^3 and so on. To go 1k codons without a stop would be (1 - p)^1000 = 1.4e-21.

However that assumes each nucleotide in the sequence is totally independent of the others, which is not at all true. It would be better to find data on the distribution of nucleotides between stop codons in various genomes