diff --git a/plenum/test/instances/test_instance_cannot_become_active_with_less_than_four_servers.py b/plenum/test/instances/test_instance_cannot_become_active_with_less_than_four_servers.py
index 036bc6c931..d9e2b2d7d0 100644
--- a/plenum/test/instances/test_instance_cannot_become_active_with_less_than_four_servers.py
+++ b/plenum/test/instances/test_instance_cannot_become_active_with_less_than_four_servers.py
@@ -60,6 +60,8 @@ def addNodeBackAndCheck(nodeIdx: int, expectedStatus: Status):
 
                 timeout = waits.expectedNodeStartUpTimeout() + \
                     waits.expectedPoolInterconnectionTime(len(nodeSet))
+                # TODO: Probably it's better to modify waits.* functions
+                timeout *= 1.5
                 looper.run(eventually(checkNodeStatusRemotesAndF,
                                       expectedStatus,
                                       nodeIdx,
diff --git a/plenum/test/node_catchup/test_node_catchup_after_restart_after_txns.py b/plenum/test/node_catchup/test_node_catchup_after_restart_after_txns.py
index 9e98d40a2a..ab8e414f21 100644
--- a/plenum/test/node_catchup/test_node_catchup_after_restart_after_txns.py
+++ b/plenum/test/node_catchup/test_node_catchup_after_restart_after_txns.py
@@ -73,10 +73,13 @@ def test_node_catchup_after_restart_with_txns(
     looper.add(newNode)
     txnPoolNodeSet[-1] = newNode
 
+    # Make sure ledger is not synced initially
+    check_ledger_state(newNode, DOMAIN_LEDGER_ID, LedgerState.not_synced)
+
     # Delay catchup reply processing so LedgerState does not change
-    # TODO fix delay, sometimes it's not enough and loweer 'check_ledger_state'
+    # TODO fix delay, sometimes it's not enough and lower 'check_ledger_state'
     # fails because newNode's domain ledger state is 'synced'
-    delay_catchup_reply = 5
+    delay_catchup_reply = 10
     newNode.nodeIbStasher.delay(cr_delay(delay_catchup_reply))
     looper.run(checkNodesConnected(txnPoolNodeSet))
 
diff --git a/plenum/test/node_request/test_timestamp/test_timestamp_post_view_change.py b/plenum/test/node_request/test_timestamp/test_timestamp_post_view_change.py
index a3aef6e1ec..53538e69b7 100644
--- a/plenum/test/node_request/test_timestamp/test_timestamp_post_view_change.py
+++ b/plenum/test/node_request/test_timestamp/test_timestamp_post_view_change.py
@@ -7,6 +7,7 @@
 from plenum.test.test_node import ensureElectionsDone, getNonPrimaryReplicas
 from plenum.test.view_change.helper import ensure_view_change
 from plenum.test.helper import sdk_send_random_and_check, sdk_send_random_requests
+from plenum.test.delayers import icDelay
 
 Max3PCBatchSize = 4
 
@@ -51,15 +52,27 @@ def test_new_primary_has_wrong_clock(tconf, looper, txnPoolNodeSet,
 
     old_view_no = txnPoolNodeSet[0].viewNo
 
+    # Delay parameters
+    malicious_batch_count = 5
+    malicious_batch_interval = 2
+    instance_change_delay = 1.5 * malicious_batch_count * malicious_batch_interval
+
+    # Delay instance change so view change doesn't happen in the middle of this test
+    for node in txnPoolNodeSet:
+        node.nodeIbStasher.delay(icDelay(instance_change_delay))
+
     # Requests are sent
-    for _ in range(5):
+    for _ in range(malicious_batch_count):
         sdk_send_random_requests(looper,
                                 sdk_pool_handle,
                                 sdk_wallet_client,
                                 count=2)
-        looper.runFor(.2)
+        looper.runFor(malicious_batch_interval)
 
     def chk():
+        for node in txnPoolNodeSet:
+            assert node.viewNo == old_view_no
+
         for node in [n for n in txnPoolNodeSet if n != faulty_node]:
             # Each non faulty node raises suspicion
             assert get_timestamp_suspicion_count(node) > susp_counts[node.name]
@@ -70,6 +83,10 @@ def chk():
 
     looper.run(eventually(chk, retryWait=1))
 
+    # Clear delays
+    for node in txnPoolNodeSet:
+        node.nodeIbStasher.reset_delays_and_process_delayeds()
+
     # Eventually another view change happens
     looper.run(eventually(checkViewNoForNodes, txnPoolNodeSet, old_view_no + 1,
                           retryWait=1, timeout=2 * tconf.PerfCheckFreq))