diff --git a/lib/src/main/kotlin/at/bitfire/ical4android/validation/FixInvalidDayOffsetPreprocessor.kt b/lib/src/main/kotlin/at/bitfire/ical4android/validation/FixInvalidDayOffsetPreprocessor.kt
index 54559628..a1017138 100644
--- a/lib/src/main/kotlin/at/bitfire/ical4android/validation/FixInvalidDayOffsetPreprocessor.kt
+++ b/lib/src/main/kotlin/at/bitfire/ical4android/validation/FixInvalidDayOffsetPreprocessor.kt
@@ -14,7 +14,8 @@ object FixInvalidDayOffsetPreprocessor : StreamPreprocessor() {
         // Examples:
         // TRIGGER:-P2DT
         // TRIGGER:-PT2D
-        "^(DURATION|TRIGGER):-?P((T-?\\d+D)|(-?\\d+DT))\$",
+        // REFRESH-INTERVAL;VALUE=DURATION:PT1D
+        "(?:^|=)(DURATION|TRIGGER):-?P((T-?\\d+D)|(-?\\d+DT))",
         setOf(RegexOption.MULTILINE, RegexOption.IGNORE_CASE)
     )