diff --git a/app/src/androidTest/java/app/opendocument/droid/test/ScreenshotTests.kt b/app/src/androidTest/java/app/opendocument/droid/test/ScreenshotTests.kt
index 2cadd02cb36d..7b70c9d54f41 100644
--- a/app/src/androidTest/java/app/opendocument/droid/test/ScreenshotTests.kt
+++ b/app/src/androidTest/java/app/opendocument/droid/test/ScreenshotTests.kt
@@ -86,7 +86,7 @@ import org.junit.runner.RunWith
  * ./gradlew connectedProDebugAndroidTest \
  *     -Pandroid.testInstrumentationRunnerArguments.class=app.opendocument.droid.test.ScreenshotTests \
  *     -Pandroid.testInstrumentationRunnerArguments.device=phone \
- *     -Pandroid.testInstrumentationRunnerArguments.locales=en-US,de-DE
+ *     -Pandroid.testInstrumentationRunnerArguments.locales=en-US+de-DE
  * ```
  *
  * Wants android 15 or newer, and says so rather than photographing what an older one draws.
@@ -599,7 +599,11 @@ class ScreenshotTests {
 
     // --- what the run was asked for -----------------------------------------
 
-    /** The locales to photograph: every one the listing is written in, unless fewer were named. */
+    /**
+     * The locales to photograph: every one the listing is written in, unless fewer were named.
+     *
+     * A plus separates them as well as a comma, which AGP 9.4.0 cuts such a property at.
+     */
     private fun locales(spoken: JSONObject): List<String> {
         val known = spoken.keys().asSequence().sorted().toList()
 
@@ -608,7 +612,7 @@ class ScreenshotTests {
             return known
         }
 
-        val wanted = given.split(",").map { it.trim() }.filter { it.isNotEmpty() }
+        val wanted = given.split(',', '+').map { it.trim() }.filter { it.isNotEmpty() }
         val unknown = wanted.filterNot { it in known }
         Assert.assertTrue(
             "no such locale: ${unknown.joinToString()}. One of ${known.joinToString()}",
diff --git a/fastlane/Fastfile b/fastlane/Fastfile
index 28204ca10a56..0efd4f19f6fe 100644
--- a/fastlane/Fastfile
+++ b/fastlane/Fastfile
@@ -330,7 +330,8 @@ platform :android do
         "android.testInstrumentationRunnerArguments.class" =>
           "app.opendocument.droid.test.ScreenshotTests",
         "android.testInstrumentationRunnerArguments.device" => device,
-        "android.testInstrumentationRunnerArguments.locales" => languages.join(",")
+        # a plus, not a comma: AGP 9.4.0 cuts one of these at the first comma
+        "android.testInstrumentationRunnerArguments.locales" => languages.join("+")
       }
     )
 
@@ -342,6 +343,16 @@ platform :android do
       )
     end
 
+    # a short list photographs as a complete run, so the count is what catches it.
+    # Per language rather than as a set, which a release runner does not have.
+    missing = languages - taken.map { |path| File.basename(File.dirname(path)) }.uniq
+    unless missing.empty?
+      UI.user_error!(
+        "the run photographed #{missing.length} of #{languages.length} languages: " \
+        "nothing came out for #{missing.join(', ')}"
+      )
+    end
+
     FileUtils.mkdir_p(SCREENSHOT_DIR)
     taken.each do |path|
       locale = File.basename(File.dirname(path))