NoMethodError undefined method 'assert_valid_keys' for true:TrueClass

[ran5000]

iv'e found something interesting, ever since i've installed multi_db

MyModel.connection.transaction do
test = 1+2
end
return the following exception (in most cases): NoMethodError undefined method 'assert_valid_keys' for true:TrueClass

but if i run:

MyModel.connection.transaction({}) do
test = 1+2
end
everything runs smoothly.

my gut filling tells me that multi_db (which is based on masochism gem) doesnt "play nice" with one of the other gems im using ( maybe: deadlock_retry or ar-extensions).

any ideas?