diff --git a/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_deposit.py b/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_deposit.py
index f7f468b367..2bc29009ff 100644
--- a/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_deposit.py
+++ b/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_deposit.py
@@ -19,6 +19,8 @@
 def test_effective_deposit_with_previous_fork_version(spec, state):
     assert state.fork.previous_version != state.fork.current_version
 
+    # It's only effective in Altair because the default `fork_version` of `compute_domain` is `GENESIS_FORK_VERSION`.
+    # Therefore it's just a normal `DepositMessage`.
     yield from run_deposit_processing_with_specific_fork_version(
         spec,
         state,
diff --git a/tests/core/pyspec/eth2spec/test/bellatrix/block_processing/test_process_deposit.py b/tests/core/pyspec/eth2spec/test/bellatrix/block_processing/test_process_deposit.py
index 24c94bac68..c88463b7ab 100644
--- a/tests/core/pyspec/eth2spec/test/bellatrix/block_processing/test_process_deposit.py
+++ b/tests/core/pyspec/eth2spec/test/bellatrix/block_processing/test_process_deposit.py
@@ -12,6 +12,8 @@
 @spec_state_test
 @always_bls
 def test_ineffective_deposit_with_previous_fork_version(spec, state):
+    # Since deposits are valid across forks, the domain is always set with `GENESIS_FORK_VERSION`.
+    # It's an ineffective deposit because it fails at BLS sig verification.
     # NOTE: it was effective in Altair.
     assert state.fork.previous_version != state.fork.current_version