Pool is unable to write NYMs after BLS keys enabling

Build Info:
indy-node 1.2.47

Steps to Reproduce:
1. Install 1.1.43 version pool.
2. Perform upgrade with force=False to 1.2.47 version.
3. Run enable_bls script as indy user from all nodes, e.g.:

enable_bls --name=Node1 --node_dest=Gw6pDLhcBcoQesN72qfotTgFa7cbuqZpkX3Xo6pLhPhv --steward_seed=000000000000000000000000Steward1 --bls_seed=000000000000000000000000Steward1

enable_bls --name=Node2 --node_dest=8ECVSk179mjsjKRLWiQtssMLgp6EPhWXtaYyStWPSGAb --steward_seed=000000000000000000000000Steward2 --bls_seed=000000000000000000000000Steward2

enable_bls --name=Node3 --node_dest=DKVxG2fXXTU8yT5N7hGEbXB3dfdAnYv1JczDUHpmDxya --steward_seed=000000000000000000000000Steward3 --bls_seed=000000000000000000000000Steward3

enable_bls --name=Node4 --node_dest=4PS3EDQ3dW1tci1Bp6543CfuuebjFrg36kLAUcskGfaA --steward_seed=000000000000000000000000Steward4 --bls_seed=000000000000000000000000Steward4

4. Check /var/lib/indy/sandbox/keys/NodeX/bls_keys.
5. Check logs for "bls" entries.
6. Send and get some NYMs (it works).
7. Restart all nodes.
8. Check logs for "bls" entries.
9. Send and get some NYMs (NYMs adding doesn't work).

Actual Results:
There is an error in Step 3:

Traceback (most recent call last):
File "/usr/local/bin/enable_bls", line 115, in <module>
send_node_txn(node_name, bls_key, steward_seed, node_dest)
File "/usr/local/bin/enable_bls", line 54, in send_node_txn
client = Client(name, ha=ha)
File "/usr/local/lib/python3.5/dist-packages/indy_client/client/client.py", line 51, in _init_
sighex)
File "/usr/local/lib/python3.5/dist-packages/plenum/client/client.py", line 151, in _init_
sighex)
File "/usr/local/lib/python3.5/dist-packages/plenum/common/stacks.py", line 73, in _init_
seed=seed, sighex=sighex, config=config)
File "/usr/local/lib/python3.5/dist-packages/stp_zmq/kit_zstack.py", line 29, in _init_
msgRejectHandler=msgRejectHandler)
File "/usr/local/lib/python3.5/dist-packages/stp_zmq/simple_zstack.py", line 39, in _init_
msgRejectHandler=msgRejectHandler)
File "/usr/local/lib/python3.5/dist-packages/stp_zmq/zstack.py", line 81, in _init_
self.setupDirs()
File "/usr/local/lib/python3.5/dist-packages/stp_zmq/zstack.py", line 263, in setupDirs
os.makedirs(d, exist_ok=True)
File "/usr/lib/python3.5/os.py", line 231, in makedirs
makedirs(head, mode, exist_ok)
File "/usr/lib/python3.5/os.py", line 241, in makedirs
mkdir(name, mode)
PermissionError: [Errno 13] Permission denied: 'keys'

BLS keys looks like added (Step 4) but not enabled (Step 5). Nodes restarting activates BLS on nodes (Step 8) but pool can read NYMs only after that (Step 9).