diff --git a/tests/generators/generate-luks2-non-compact-json-4k-token-0.img.sh b/tests/generators/generate-luks2-non-compact-json-4k-token-0.img.sh
new file mode 100755
index 00000000..abbaf5a7
--- /dev/null
+++ b/tests/generators/generate-luks2-non-compact-json-4k-token-0.img.sh
@@ -0,0 +1,58 @@
+#!/bin/bash
+
+. lib.sh
+
+#
+# *** Description ***
+#
+# generate LUKS2 header with non compact (valid!)
+# json and additional token with id 0 with json
+# format aligned to 4K boundary.
+#
+# The image is tested for correct LUKS2 write optimization
+# where non compact json trailing bytes must not remain in LUKS2 json
+# area after write of shorter (e.g. compact) json.
+
+# $1 full target dir
+# $2 full source luks2 image
+
+generate()
+{
+	# add empty token
+	json_str=$(jq -c '.tokens."0" = {"type":"a", "keyslots":[]}' $TMPDIR/json0)
+	json_len_orig=${#json_str}
+	test $json_len_orig -lt $((LUKS2_JSON_SIZE*512)) || exit 2
+
+	# align to 4k and full 4K of whitespace if already aligned
+	json_fill_len=$((4096-(json_len_orig%4096)))
+	fill=$(repeat_str " " $json_fill_len)
+	json_str_new=$(echo -e $json_str | sed -e "s/\(\"type\":\)\(\"luks2\"\)/\1""$fill""\2/")
+	json_len_new=${#json_str_new}
+
+	test $((json_len_new%4096)) -eq 0 || exit 2
+	test $json_len_new -lt $((LUKS2_JSON_SIZE*512)) || exit 2
+	test $json_len_new -gt $json_len_orig || exit 2
+
+	printf '%s' "$json_str_new" | _dd of=$TMPDIR/json0 bs=4K conv=notrunc
+	printf '%s' "$json_str_new" | _dd of=$TMPDIR/json1 bs=4K conv=notrunc
+
+	lib_mangle_json_hdr0
+	lib_mangle_json_hdr1
+}
+
+check()
+{
+	lib_hdr0_checksum || exit 2
+	lib_hdr1_checksum || exit 2
+
+	read_luks2_json0 $TGT_IMG $TMPDIR/json_res0
+
+	read -r json_str_res < $TMPDIR/json_res0
+	test $((${#json_str_res}%4096)) -eq 0 || exit 2
+	test ${#json_str_res} -gt $json_len_orig || exit 2
+}
+
+lib_prepare $@
+generate
+check
+lib_cleanup
diff --git a/tests/generators/generate-luks2-non-compact-json-token-0.img.sh b/tests/generators/generate-luks2-non-compact-json-token-0.img.sh
new file mode 100755
index 00000000..e5f5208a
--- /dev/null
+++ b/tests/generators/generate-luks2-non-compact-json-token-0.img.sh
@@ -0,0 +1,52 @@
+#!/bin/bash
+
+. lib.sh
+
+#
+# *** Description ***
+#
+# generate LUKS2 header with non compact (valid!)
+# json and additional token with id 0.
+#
+# The image is tested for correct LUKS2 write optimization
+# where non compact json trailing bytes must not remain in LUKS2 json
+# area after write of shorter (e.g. compact) json.
+
+# $1 full target dir
+# $2 full source luks2 image
+
+generate()
+{
+	# add empty token
+	json_str=$(jq -c '.tokens."0" = {"type":"a", "keyslots":[]}' $TMPDIR/json0)
+	json_len_orig=${#json_str}
+	test $json_len_orig -lt $((LUKS2_JSON_SIZE*512)) || exit 2
+
+	json_str_new=$(echo -n $json_str | sed -e 's/\(\"type\":\)\(\"luks2\"\)/\1 \2/')
+	json_len_new=${#json_str_new}
+
+	test $json_len_new -lt $((LUKS2_JSON_SIZE*512)) || exit 2
+	test $json_len_new -gt $json_len_orig || exit 2
+
+	printf '%s' "$json_str_new" | _dd of=$TMPDIR/json0 bs=1 conv=notrunc
+	printf '%s' "$json_str_new" | _dd of=$TMPDIR/json1 bs=1 conv=notrunc
+
+	lib_mangle_json_hdr0
+	lib_mangle_json_hdr1
+}
+
+check()
+{
+	lib_hdr0_checksum || exit 2
+	lib_hdr1_checksum || exit 2
+
+	read_luks2_json0 $TGT_IMG $TMPDIR/json_res0
+
+	read -r json_str_res < $TMPDIR/json_res0
+	test ${#json_str_res} -gt $json_len_orig || exit 2
+}
+
+lib_prepare $@
+generate
+check
+lib_cleanup
diff --git a/tests/luks2-validation-test b/tests/luks2-validation-test
index a09c5e84..47e631fe 100755
--- a/tests/luks2-validation-test
+++ b/tests/luks2-validation-test
@@ -73,6 +73,20 @@ test_load()
 	test -z "$_DEBUG" || _debug="--debug"
 
 	case "$1" in
+	T)
+		if [ -n "$_debug" ]; then
+			$CRYPTSETUP token remove --token-id 0 $_debug $IMG
+		else
+			$CRYPTSETUP token remove --token-id 0 $IMG > /dev/null 2>&1
+		fi
+		test $? -eq 0 || return 1
+		if [ -n "$_debug" ]; then
+			$CRYPTSETUP luksDump $_debug $IMG
+		else
+			$CRYPTSETUP luksDump $IMG > /dev/null 2>&1
+		fi
+		test $? -eq 0 || return 1
+		;;
 	R)
 		if [ -n "$_debug" ]; then
 			$CRYPTSETUP luksDump $_debug $IMG
@@ -255,6 +269,10 @@ RUN luks2-keyslot-invalid-area-size.img			"F" "Invalid keyslot area size that ca
 RUN luks2-keyslot-invalid-objects.img			"F" "Invalid keyslot objects not rejected"
 RUN luks2-keyslot-invalid-af.img			"F" "Invalid keyslot objects types not rejected"
 
+echo "[8] Test non compact json does not break write optimization"
+RUN luks2-non-compact-json-token-0.img			"T" "Non compact json area corrupted after write"
+RUN luks2-non-compact-json-4k-token-0.img		"T" "Non compact 4K aligned json area corrupted after write"
+
 remove_mapping
 
 test $FAILS -eq 0 || fail "($FAILS wrong result(s) in total)"