diff --git a/src/main/java/picocli/CommandLine.java b/src/main/java/picocli/CommandLine.java
index feb32e8b2..2a84f2ad0 100644
--- a/src/main/java/picocli/CommandLine.java
+++ b/src/main/java/picocli/CommandLine.java
@@ -14326,10 +14326,10 @@ private void consumeMapArguments(ArgSpec argSpec,
                 alreadyUnquoted = false;
             }
             // now process the varargs if any
-            String fallback = consumed == 0 && argSpec.isOption() && !OptionSpec.DEFAULT_FALLBACK_VALUE.equals(((OptionSpec) argSpec).fallbackValue())
+            String fallback = argSpec.isOption() && !OptionSpec.DEFAULT_FALLBACK_VALUE.equals(((OptionSpec) argSpec).fallbackValue())
                     ? ((OptionSpec) argSpec).fallbackValue()
                     : null;
-            if (fallback != null && (args.isEmpty() || !varargCanConsumeNextValue(argSpec, args.peek())
+            if (fallback != null && consumed == 0 && (args.isEmpty() || !varargCanConsumeNextValue(argSpec, args.peek())
                     || !canConsumeOneMapArgument(argSpec, lookBehind, alreadyUnquoted, arity, consumed, args.peek(), classes, keyConverter, valueConverter, argDescription))) {
                 args.push(fallback);
             }
@@ -14548,11 +14548,11 @@ private List<Object> consumeArguments(ArgSpec argSpec,
                 consumed = addUserInputToList(argSpec, result, consumed, argDescription);
             }
             // now process the varargs if any
-            String fallback = consumed == 0 && argSpec.isOption() && !OptionSpec.DEFAULT_FALLBACK_VALUE.equals(((OptionSpec) argSpec).fallbackValue())
+            String fallback = argSpec.isOption() && !OptionSpec.DEFAULT_FALLBACK_VALUE.equals(((OptionSpec) argSpec).fallbackValue())
                     ? ((OptionSpec) argSpec).fallbackValue()
                     : null;
             boolean hasFallback = fallback != null || (argSpec.isOption() && Option.NULL_VALUE.equals(((OptionSpec) argSpec).originalFallbackValue));
-            if (hasFallback && (args.isEmpty() || !varargCanConsumeNextValue(argSpec, args.peek())
+            if (hasFallback && consumed == 0 && (args.isEmpty() || !varargCanConsumeNextValue(argSpec, args.peek())
                     || (!canConsumeOneArgument(argSpec, lookBehind, alreadyUnquoted, arity, consumed, args.peek(), argDescription)))) {
                 args.push(fallback);
             }
diff --git a/src/test/java/picocli/FallbackTest.java b/src/test/java/picocli/FallbackTest.java
index e0f4df48c..750582d3b 100644
--- a/src/test/java/picocli/FallbackTest.java
+++ b/src/test/java/picocli/FallbackTest.java
@@ -227,4 +227,60 @@ public void testIssue1993Map() {
         Map<String, String> expected = TestUtil.mapOf("KEY", CommandLine.Option.NULL_VALUE, "FOO", "123");
         assertEquals(expected, main.map);
     }
+
+
+    static class Issue1998NPE {
+        static final String MY_NULL_VALUE = "_MY_" + CommandLine.Option.NULL_VALUE;
+
+        @CommandLine.Option(names = {"--item"}, arity = "0..1", fallbackValue = CommandLine.Option.NULL_VALUE)
+        List<String> item;
+        @CommandLine.Option(names = {"--item2"}, arity = "0..1", fallbackValue = MY_NULL_VALUE, converter = ItemNullValueConverter.class)
+        List<String> item2;
+    }
+
+    static class ItemNullValueConverter implements CommandLine.ITypeConverter<String> {
+        public String convert(String value) throws Exception {
+            if (value.equals(Issue1998NPE.MY_NULL_VALUE)) {
+                return null;
+            }
+            return value;
+        }
+    }
+
+    @Test  // PASS
+    public void testIssue1998_item__null() {
+        Issue1998NPE main = new Issue1998NPE();
+        CommandLine commandLine = new CommandLine(main);
+        commandLine.parseArgs("--item", "--item", "pepa");
+
+        assertEquals(Arrays.asList(null, "pepa"), main.item);
+    }
+
+    @Test  // FAIL
+    public void testIssue1998_item__empty_equals() {
+        Issue1998NPE main = new Issue1998NPE();
+        CommandLine commandLine = new CommandLine(main);
+        commandLine.parseArgs("--item=", "--item", "pepa");
+
+        assertEquals(Arrays.asList("", "pepa"), main.item);
+    }
+
+    @Test  // PASS
+    public void testIssue1998_item2__null() {
+        Issue1998NPE main = new Issue1998NPE();
+        CommandLine commandLine = new CommandLine(main);
+        commandLine.parseArgs("--item2", "--item2", "pepa");
+
+        assertEquals(Arrays.asList(null, "pepa"), main.item2);
+    }
+
+    @Test  // PASS
+    public void testIssue1998_item2__empty_equals() {
+        Issue1998NPE main = new Issue1998NPE();
+        CommandLine commandLine = new CommandLine(main);
+        commandLine.parseArgs("--item2=", "--item2", "pepa");
+
+        assertEquals(Arrays.asList("", "pepa"), main.item2);
+    }
+
 }