diff --git a/src/logging/writers/ascii/Ascii.cc b/src/logging/writers/ascii/Ascii.cc
index 3d43964422..2a9ed25c7d 100644
--- a/src/logging/writers/ascii/Ascii.cc
+++ b/src/logging/writers/ascii/Ascii.cc
@@ -749,10 +749,9 @@ void Ascii::RotateLeftoverLogs() {
         auto ppf = default_ppf;
 
         if ( ! ll.post_proc_func.empty() ) {
-            auto func = id::find_func(ll.post_proc_func.data());
-
-            if ( func )
-                ppf = std::move(func);
+            const auto& id = id::find(ll.post_proc_func.data());
+            if ( id && id->GetVal() && same_type(id->GetVal()->GetType(), default_ppf->GetType()) )
+                ppf = id->GetVal()->AsFuncVal()->AsFuncPtr();
             else
                 reporter->Warning(
                     "Could not postprocess log '%s' with intended "
diff --git a/testing/btest/Baseline/scripts.base.frameworks.logging.rotate-leftover-log-rotation-shadow-files-postprocessor-errors/.stderr b/testing/btest/Baseline/scripts.base.frameworks.logging.rotate-leftover-log-rotation-shadow-files-postprocessor-errors/.stderr
new file mode 100644
index 0000000000..0dfb7a961f
--- /dev/null
+++ b/testing/btest/Baseline/scripts.base.frameworks.logging.rotate-leftover-log-rotation-shadow-files-postprocessor-errors/.stderr
@@ -0,0 +1,6 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+### NOTE: This file has been sorted with diff-sort.
+Rotated/postprocessed leftover log '<...>/conn.log' -> 'conn.no-date.log' 
+Rotated/postprocessed leftover log '<...>/dns.log' -> 'dns.no-date.log' 
+warning: Could not postprocess log '<...>/conn.log' with intended postprocessor function 'non_existing_rotation_postprocessor', proceeding  with the default function
+warning: Could not postprocess log '<...>/dns.log' with intended postprocessor function 'wrongly_typed_rotation_postprocessor', proceeding  with the default function
diff --git a/testing/btest/Baseline/scripts.base.frameworks.logging.rotate-leftover-log-rotation-shadow-files-postprocessor-errors/logs.cat b/testing/btest/Baseline/scripts.base.frameworks.logging.rotate-leftover-log-rotation-shadow-files-postprocessor-errors/logs.cat
new file mode 100644
index 0000000000..05dd1c9670
--- /dev/null
+++ b/testing/btest/Baseline/scripts.base.frameworks.logging.rotate-leftover-log-rotation-shadow-files-postprocessor-errors/logs.cat
@@ -0,0 +1,3 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+leftover conn log
+leftover dns log
diff --git a/testing/btest/scripts/base/frameworks/logging/rotate-leftover-log-rotation-shadow-files-postprocessor-errors.zeek b/testing/btest/scripts/base/frameworks/logging/rotate-leftover-log-rotation-shadow-files-postprocessor-errors.zeek
new file mode 100644
index 0000000000..42e25ff17d
--- /dev/null
+++ b/testing/btest/scripts/base/frameworks/logging/rotate-leftover-log-rotation-shadow-files-postprocessor-errors.zeek
@@ -0,0 +1,32 @@
+# @TEST-DOC: Put a non-existing postprocessor function into a shadow file, ensure the default gets picked up. Regression test for #4562
+#
+# @TEST-EXEC: echo ".log" >> .shadow.conn.log
+# @TEST-EXEC: echo "non_existing_rotation_postprocessor" >> .shadow.conn.log
+# @TEST-EXEC: echo "leftover conn log" > conn.log
+#
+# @TEST-EXEC: echo ".log" >> .shadow.dns.log
+# @TEST-EXEC: echo "wrongly_typed_rotation_postprocessor" >> .shadow.dns.log
+# @TEST-EXEC: echo "leftover dns log" > dns.log
+#
+# @TEST-EXEC: zeek -b %INPUT
+# @TEST-EXEC: TEST_DIFF_CANONIFIER="$SCRIPTS/diff-remove-abspath | $SCRIPTS/diff-sort" btest-diff .stderr
+#
+# Ensure leftover files were removed.
+# @TEST-EXEC: ! test -f .shadow.conn.log
+# @TEST-EXEC: ! test -f conn.log
+# @TEST-EXEC: ! test -f .shadow.dns.log
+# @TEST-EXEC: ! test -f dns.log
+#
+# Ensure the rotated conn log ends-up in the current working directory.
+# @TEST-EXEC: cat ./conn.*.log ./dns.*.log > logs.cat
+# @TEST-EXEC: btest-diff logs.cat
+
+function wrongly_typed_rotation_postprocessor(): bool
+	{
+	exit(1);
+	return T;
+	}
+
+redef LogAscii::enable_leftover_log_rotation = T;
+redef Log::default_rotation_interval = 1hr;
+redef Log::default_rotation_date_format = "no-date";