RECEIVED:
[# ProcessedTransaction id: 76105, raw_transaction_id: 38058, category_id: nil, amount: -21588, transaction_order: 0, automatic_fill: false ]

I've noticed the same thing with .joins + .limit

I've created a test app (attached) which shows the problems [test/unit/user_test.rb]

This FAILS:
assert_equal User.find_by_sql(User.joins(:user_foo).limit(12).to_sql).size, User.joins(:user_foo).limit(12).size

On the console, oddly, if I assign the Relation to a variable and then test .size on it, I get the correct result.

in the console rails c test:

u = User.joins(:user_foo).limit(12) => ....
u.size => 12
u.size == User.joins(:user_foo).limit(12).size => false

But in the test this fails:
u = User.joins(:user_foo).limit(12)
assert_equal 12, u.size

In the mean time, a work around, is to wrap in User.find_by_sql(User.joins(:user_foo).limit(12).to_sql)

@Eugene

Can you post migration and model for the ProcessedTransaction and RawTransaction? I will look into this issue.