Baffled by error running rake rspec:models

In my application, we connect to 2 databases, so we make a lot of
specs to test this type of interaction. When I run individual model
specs using spec, or using rake spec SPEC=xxx, they run fine. When I
run rake spec:models, all the specs which connect to the 2nd database
fail on errors like this:

OCIError in ‘WellLicense should identify EIS data is not available’
ORA-01017: invalid username/password; logon denied
env.c:257:in oci8lib.so
./spec/models/well_license2_spec.rb:6:in `new’
./spec/models/well_license2_spec.rb:6:

This WAS working a couple of days ago. I did update from the beta
version of the Oracle Intel InstantClient for Mac to the officially
released version, but I can’t see how that would make a difference,
especially when running the specs individually works.

This has to be some strange configuration error, but I’m baffled.
I’ve spent hours trying to track it down. Help!

database.yml entry:

data_centre:
adapter: oracle_enhanced
database: xe
username: XXXXXX
password: YYYYYY

And our database connection is established in
data_center_spec_helper.rb like so:

LabRecord
.establish_connection(ActiveRecord::Base.configurations[‘data_centre’])

Regards, Lori