diff --git a/app/src/main/java/io/github/sspanak/tt9/hacks/InputType.java b/app/src/main/java/io/github/sspanak/tt9/hacks/InputType.java
index 2233b5ec..ad5fa2f5 100644
--- a/app/src/main/java/io/github/sspanak/tt9/hacks/InputType.java
+++ b/app/src/main/java/io/github/sspanak/tt9/hacks/InputType.java
@@ -12,8 +12,18 @@ public class InputType extends StandardInputType {
 	}
 
 
+	/**
+	 * isDuoLingoReportBug
+	 * When reporting a bug in the Duolingo app, the text field is missing the TYPE_TEXT flag, which
+	 * causes us to detect it as a numeric field. This effectively disables Predictive mode, which is
+	 * actually desired there. Here, we detect this particular case and treat it as a text field.
+	 */
 	private boolean isDuoLingoReportBug() {
-		return isAppField("com.duolingo", EditorInfo.TYPE_TEXT_FLAG_NO_SUGGESTIONS);
+		return
+			field != null
+			&& "com.duolingo".equals(field.packageName)
+			&& field.inputType == EditorInfo.TYPE_TEXT_FLAG_NO_SUGGESTIONS
+			&& field.imeOptions == EditorInfo.IME_ACTION_DONE;
 	}
 
 
diff --git a/app/src/main/java/io/github/sspanak/tt9/ime/helpers/StandardInputType.java b/app/src/main/java/io/github/sspanak/tt9/ime/helpers/StandardInputType.java
index 2977d8b5..223df098 100644
--- a/app/src/main/java/io/github/sspanak/tt9/ime/helpers/StandardInputType.java
+++ b/app/src/main/java/io/github/sspanak/tt9/ime/helpers/StandardInputType.java
@@ -6,6 +6,8 @@ import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;
 
 import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
 
 import io.github.sspanak.tt9.ime.modes.InputMode;
 
@@ -131,11 +133,11 @@ abstract public class StandardInputType {
 	 * @return ArrayList<SettingsStore.MODE_ABC | SettingsStore.MODE_123 | SettingsStore.MODE_PREDICTIVE>
 	 */
 	public ArrayList<Integer> determineInputModes(Context context) {
-		ArrayList<Integer> allowedModes = new ArrayList<>();
+		Set<Integer> allowedModes = new HashSet<>();
 
 		if (field == null) {
 			allowedModes.add(InputMode.MODE_PASSTHROUGH);
-			return allowedModes;
+			return new ArrayList<>(allowedModes);
 		}
 
 		// Calculators (only 0-9 and math) and Dialer (0-9, "#" and "*") fields
@@ -143,7 +145,7 @@ abstract public class StandardInputType {
 		// Note: A Dialer field is not a Phone number field.
 		if (isSpecialNumeric(context)) {
 			allowedModes.add(InputMode.MODE_PASSTHROUGH);
-			return allowedModes;
+			return new ArrayList<>(allowedModes);
 		}
 
 		switch (field.inputType & InputType.TYPE_MASK_CLASS) {
@@ -153,7 +155,7 @@ abstract public class StandardInputType {
 				// Numbers, dates and phone numbers default to the numeric keyboard,
 				// with no extra features.
 				allowedModes.add(InputMode.MODE_123);
-				return allowedModes;
+				return new ArrayList<>(allowedModes);
 
 			case InputType.TYPE_CLASS_TEXT:
 				// This is general text editing. We will default to the
@@ -177,7 +179,7 @@ abstract public class StandardInputType {
 				allowedModes.add(InputMode.MODE_123);
 				allowedModes.add(InputMode.MODE_ABC);
 
-				return allowedModes;
+				return new ArrayList<>(allowedModes);
 		}
 	}