Unable to Post Journal in GL

We have two Primary Ledgers:

Ledger A and Ledger B

Ledger A has Secondary Ledger A.1

Ledger B has multiple Secondary Ledgers

When we try to post Journal in Ledger A, it gives following error:

"Showing unopened secondary ledger period"

We opened Period in the Secondary Ledger A.1

Tries again but still getting the same error.

Later, we opened the same Period in Ledger B and to our surprise, Journal from Ledger A got Posted.

We are unable to understand, why Ledger A's Journals have dependency on Ledger B's Periods

Any Thought?