Your dough I estimate as given your ingredients weights as 890 grams
then I reckon that you add about 10 grams both salt and yeast will
weigh approximately 900 grams after mixing. Then bulk fermeniting it
will alllow for at least 5% weight loss due to fermentation you will
end up with approximately 850 grams of molded dough prior to proofing.
Now you said that you are using a 2 lb loaf tin size( 908 grams). It
looks like you do not even have enough dough for your loaf tin<g>. Are
you sure that it is a 2lb tin?
Even with 100% bread flour the dough amount is not even enough.
A 2 lb tin was designed that the loaf weight will come ouit
approximately two pounds.
Hence the dough weight put in it should be more than 2 lbs to
accomodate the bake out loss.
Now your bread if the recipe quantities are right then adding a bake
out loss of say at least 5%you will end up with around 800 grams loaf(
barely 2 pounds)..
Sorry IMO I think There is something askew in this recipe and tin
size<g>.
But anyway that is not related to your problem, ....
But be reminded this rye bread loaf tends to promote wild breaks( like
what happened to your loaf).
you have to look at the problem carefully considering the possible
reasons I enumerated above.
Roy