diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 007c01cd86f..e4dc38469eb 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -12,10 +12,12 @@ on:
       - release
       - next
       - cran-*
+      - claude/**
   pull_request:
     branches:
       - main
       - master
+      - claude/**
   workflow_dispatch:
     inputs:
       ref:
diff --git a/.github/workflows/build-and-check.yml b/.github/workflows/build-and-check.yml
index e543c7e3a79..3d8c3ff2dce 100644
--- a/.github/workflows/build-and-check.yml
+++ b/.github/workflows/build-and-check.yml
@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - cran-*
+      - claude/**
   schedule:
     - cron: '0 2 * * *'
   workflow_dispatch:
@@ -21,7 +22,7 @@ jobs:
     name: Sanitizer
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
@@ -34,7 +35,11 @@ jobs:
       - name: run sanitizer
         uses: addnab/docker-run-action@v3
         with:
-          image: ghcr.io/cynkra/docker-images/r-debug-csan-igraph:latest
+          # Built daily from https://github.com/cynkra/r-debug, so R-devel is
+          # at most a day old.
+          # The images under ghcr.io/cynkra/docker-images are no longer
+          # rebuilt; their R-devel is stale.
+          image: ghcr.io/cynkra/r-debug/r-debug-csan-igraph:latest
           options: --rm --platform linux/amd64 -v ${{ github.workspace }}:/rigraph
           run: |
             set -e
diff --git a/src/rinterface_extra.c b/src/rinterface_extra.c
index b9699995125..0ffcc2f4d40 100644
--- a/src/rinterface_extra.c
+++ b/src/rinterface_extra.c
@@ -6157,8 +6157,14 @@ SEXP Rx_igraph_is_chordal(SEXP graph, SEXP alpha, SEXP alpham1,
   SEXP result, names;
                                         /* Convert input */
   Rz_SEXP_to_igraph(graph, &c_graph);
-  if (!Rf_isNull(alpha)) { Rz_SEXP_to_vector_int_copy(alpha, &c_alpha); }
-  if (!Rf_isNull(alpham1)) { Rz_SEXP_to_vector_int_copy(alpham1, &c_alpham1); }
+  if (!Rf_isNull(alpha)) {
+    IGRAPH_R_CHECK(Rz_SEXP_to_vector_int_copy(alpha, &c_alpha));
+    IGRAPH_FINALLY_PV(igraph_vector_int_destroy, &c_alpha);
+  }
+  if (!Rf_isNull(alpham1)) {
+    IGRAPH_R_CHECK(Rz_SEXP_to_vector_int_copy(alpham1, &c_alpham1));
+    IGRAPH_FINALLY_PV(igraph_vector_int_destroy, &c_alpham1);
+  }
   if (LOGICAL(pfillin)[0]) {
     if (0 != igraph_vector_int_init(&c_fillin, 0)) {
       igraph_error("", __FILE__, __LINE__, IGRAPH_ENOMEM);
@@ -6187,6 +6193,16 @@ SEXP Rx_igraph_is_chordal(SEXP graph, SEXP alpha, SEXP alpham1,
   } else {
     PROTECT(newgraph=R_NilValue);
   }
+  /* Unwound in reverse order of registration, so that IGRAPH_FINALLY_CLEAN()
+   * pops the entry that belongs to the vector being destroyed. */
+  if (!Rf_isNull(alpham1)) {
+    igraph_vector_int_destroy(&c_alpham1);
+    IGRAPH_FINALLY_CLEAN(1);
+  }
+  if (!Rf_isNull(alpha)) {
+    igraph_vector_int_destroy(&c_alpha);
+    IGRAPH_FINALLY_CLEAN(1);
+  }
   SET_VECTOR_ELT(result, 0, chordal);
   SET_VECTOR_ELT(result, 1, fillin);
   SET_VECTOR_ELT(result, 2, newgraph);
diff --git a/tests/testthat/test-foreign.R b/tests/testthat/test-foreign.R
index d0c29e32e7b..0332707c7e9 100644
--- a/tests/testthat/test-foreign.R
+++ b/tests/testthat/test-foreign.R
@@ -63,7 +63,7 @@ test_that("graph_from_graphdb works", {
   skip_on_cran()
 
   # Bug in base R? Checked with 2024-11-01 r87285:
-  # docker run --rm -ti -v $PWD:/rigraph -e MAKEFLAGS=-j4 ghcr.io/cynkra/docker-images/rigraph-san:latest RDcsan -q -e 'filename <- "/rigraph/DESCRIPTION"; gz_file_con <- file(filename, open = "rb"); file_con <- gzcon(gz_file_con); close(file_con); gc()'
+  # docker run --rm -ti -v $PWD:/rigraph -e MAKEFLAGS=-j4 ghcr.io/cynkra/r-debug/r-debug-csan-igraph:latest RDcsan -q -e 'filename <- "/rigraph/DESCRIPTION"; gz_file_con <- file(filename, open = "rb"); file_con <- gzcon(gz_file_con); close(file_con); gc()'
   skip_if(Sys.getenv("R_SANITIZER") == "true")
 
   expect_silent(graph_from_graphdb(nodes = 1000))