diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 94babe39..05e24bce 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -12,10 +12,10 @@ on:
 
 jobs:
   julia:
-    name: Test (${{ matrix.os }}, julia ${{ matrix.jlversion }})
+    name: Test Julia (${{ matrix.jlversion }} on ${{ matrix.os }})
     runs-on: ${{ matrix.os }}
     strategy:
-      fail-fast: true
+      fail-fast: false
       matrix:
         arch: [x64] # x86 unsupported by MicroMamba
         os: [ubuntu-latest, windows-latest, macos-latest]
@@ -50,13 +50,13 @@ jobs:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
   python:
-    name: Test (${{ matrix.os }}, python ${{ matrix.pyversion }})
+    name: Test Python (${{ matrix.pyversion }} on ${{ matrix.os }})
     runs-on: ${{ matrix.os }}
     strategy:
-      fail-fast: true
+      fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        pyversion: [">=3.8", "3.8"]
+        pyversion: ["3", "3.13.2", "3.13.1", "3.13.0", "3.12", "3.8"]
 
     steps:
       - uses: actions/checkout@v4
@@ -93,8 +93,15 @@ jobs:
           uv run pytest -s --nbval --cov=pysrc ./pytest/
         env:
           PYTHON_JULIACALL_THREADS: '2'
+          PYTHON_JULIACALL_HANDLE_SIGNALS: 'yes'
 
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v5
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+
+      - name: Setup tmate session on failure
+        uses: mxschmitt/action-tmate@v3
+        if: ${{ failure() }}
+        with:
+          limit-access-to-actor: true
diff --git a/pytest/test_all.py b/pytest/test_all.py
index 9cdc8ce4..e6e8f861 100644
--- a/pytest/test_all.py
+++ b/pytest/test_all.py
@@ -94,8 +94,8 @@ def test_issue_433():
 def test_julia_gc():
     from juliacall import Main as jl
 
-    if jl.seval('v"1.11.0-" <= VERSION < v"1.11.3"'):
-        # Seems to be a Julia bug - hopefully fixed in 1.11.3
+    if jl.seval('v"1.11.0-" <= VERSION < v"1.11.6"'):
+        # Seems to be a Julia bug - hopefully fixed in 1.11.6
         pytest.skip("Test not yet supported on Julia 1.11+")
 
     # We make a bunch of python objects with no reference to them,
diff --git a/src/JlWrap/C.jl b/src/JlWrap/C.jl
index 7b181881..03d7ae2e 100644
--- a/src/JlWrap/C.jl
+++ b/src/JlWrap/C.jl
@@ -64,6 +64,7 @@ function _pyjl_callmethod(o::C.PyPtr, args::C.PyPtr)
 end
 
 const PYJLBUFCACHE = Dict{Ptr{Cvoid},Any}()
+const PYJLBUFCACHE_DEBUG = []
 
 @kwdef struct PyBufferInfo{N}
     # data
@@ -177,7 +178,9 @@ function _pyjl_get_buffer_impl(
 
     # internal
     cptr = Base.pointer_from_objref(c)
+    @assert !haskey(PYJLBUFCACHE, cptr)
     PYJLBUFCACHE[cptr] = c
+    push!(PYJLBUFCACHE_DEBUG, c)
     b.internal[] = cptr
 
     # obj
diff --git a/src/Utils/Utils.jl b/src/Utils/Utils.jl
index 6e7b3f4d..bff10d6b 100644
--- a/src/Utils/Utils.jl
+++ b/src/Utils/Utils.jl
@@ -21,24 +21,6 @@ function explode_union(T)
     end
 end
 
-"""
-    pointer_from_obj(x)
-
-Returns `(p, c)` where `Base.pointer_from_objref(p) === x`.
-
-The pointer remains valid provided the object `c` is not garbage collected.
-"""
-function pointer_from_obj(o::T) where {T}
-    if T.mutable
-        c = o
-        p = Base.pointer_from_objref(o)
-    else
-        c = Ref{Any}(o)
-        p = unsafe_load(Ptr{Ptr{Cvoid}}(Base.pointer_from_objref(c)))
-    end
-    p, c
-end
-
 """
     ExtraNewline(x)