diff --git a/conda_libmamba_solver/index.py b/conda_libmamba_solver/index.py
index edcc6824..b8bfe1c2 100644
--- a/conda_libmamba_solver/index.py
+++ b/conda_libmamba_solver/index.py
@@ -79,15 +79,17 @@
 from typing import Dict, Iterable, Optional, Tuple, Union
 
 import libmambapy as api
+from conda import __version__ as conda_version
 from conda.base.constants import REPODATA_FN
-from conda.base.context import context
-from conda.common.io import DummyExecutor, ThreadLimitedThreadPoolExecutor
+from conda.base.context import context, reset_context
+from conda.common.io import DummyExecutor, ThreadLimitedThreadPoolExecutor, env_var
 from conda.common.serialize import json_dump, json_load
 from conda.common.url import percent_decode, remove_auth, split_anaconda_token
 from conda.core.subdir_data import SubdirData
 from conda.models.channel import Channel
 from conda.models.match_spec import MatchSpec
 from conda.models.records import PackageRecord
+from conda.models.version import VersionOrder
 
 from .mamba_utils import set_channel_priorities
 from .state import IndexHelper
@@ -407,5 +409,27 @@ def _process_query_result(
         return result
 
 
-# for conda-build
-_CachedLibMambaIndexHelper = lru_cache(maxsize=None)(LibMambaIndexHelper)
+@lru_cache(maxsize=None)
+class _LibMambaIndexForCondaBuild(LibMambaIndexHelper):
+    """
+    See https://github.com/conda/conda-libmamba-solver/issues/386
+
+    conda-build needs to operate offline so the index doesn't get updated
+    accidentally during long build phases. However, this is only guaranteed
+    to work if https://github.com/conda/conda/pull/13357 is applied. Otherwise
+    the condarc configuration might be ignored, resulting in bad index configuration
+    and missing packages anyway.
+    """
+
+    def __init__(self, *args, **kwargs):
+        if VersionOrder(conda_version) <= VersionOrder("23.10.0"):
+            log.warning(
+                "conda-build requires conda >=23.11.0 for offline index support. "
+                "Falling back to online index. This might result in KeyError messages, "
+                "specially if the remote repodata is updated during the build phase. "
+                "See https://github.com/conda/conda-libmamba-solver/issues/386."
+            )
+            super().__init__(*args, **kwargs)
+        else:
+            with env_var("CONDA_OFFLINE", "true", callback=reset_context):
+                super().__init__(*args, **kwargs)
diff --git a/conda_libmamba_solver/solver.py b/conda_libmamba_solver/solver.py
index d52bc713..85ebb9a8 100644
--- a/conda_libmamba_solver/solver.py
+++ b/conda_libmamba_solver/solver.py
@@ -49,7 +49,7 @@
 
 from . import __version__
 from .exceptions import LibMambaUnsatisfiableError
-from .index import LibMambaIndexHelper, _CachedLibMambaIndexHelper
+from .index import LibMambaIndexHelper, _LibMambaIndexForCondaBuild
 from .mamba_utils import init_api_context, mamba_version
 from .state import SolverInputState, SolverOutputState
 from .utils import is_channel_available
@@ -175,7 +175,7 @@ def solve_final_state(
                 rec.channel: None for rec in self._index if rec.channel.scheme == "file"
             }
             # Cache indices for conda-build, it gets heavy otherwise
-            IndexHelper = _CachedLibMambaIndexHelper
+            IndexHelper = _LibMambaIndexForCondaBuild
         else:
             IndexHelper = LibMambaIndexHelper
             conda_bld_channels = ()
diff --git a/news/395-offline-conda-build b/news/395-offline-conda-build
new file mode 100644
index 00000000..f54e5c16
--- /dev/null
+++ b/news/395-offline-conda-build
@@ -0,0 +1,20 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* Instantiate `IndexHelper` in offline mode for compatibility with conda-build. Otherwise
+  the index can get out of sync during long build processes. (#386 via #395)
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>
diff --git a/tests/data/conda_build_recipes/stackvana/meta.yaml b/tests/data/conda_build_recipes/stackvana/meta.yaml
index 2991ce80..b062368a 100644
--- a/tests/data/conda_build_recipes/stackvana/meta.yaml
+++ b/tests/data/conda_build_recipes/stackvana/meta.yaml
@@ -1,4 +1,4 @@
-{% set name = "stackvana-core" %}
+{% set name = "stackvana-split" %}
 {% set version = "0.2021.43" %}
 {% set eups_product = "lsst_distrib" %}