Years ago I assembled a SB Chevy motor that had a set of the old Ansen aluminum rods that had sat on the shelf for many years before being bought for this motor, they had shrunk on the big end and needed resizing
I sent them back to Ansen and they did that for no charge and did what they describe as a ditch cut on the rod caps and told me that If the motor was going to set for more than 90 days to have the customer loosen the rod bolt and retorque them before start up when it was going to be ran again
My message is to remove them from the motor and have the big ends check for size and roundness