One of added nodes doesn't catch up

Overview:
One of added nodes doesn't catch up.

Build Info:
indy-node 1.2.234

Steps to Reproduce:
1. Install pool of 4 nodes.
2. Run load tests to fill ledger with ~20000 txns.
3. Add the 5th node.
4. Send NYM txn.
5. Add the 6th node.
6. Send NYM.

Actual Results:
Node 5 doesn't catch up (but Node 6 does and pool works normally).

Expected Results:
Node 5 should catch up.