diff --git a/src/lib/ical-io.js b/src/lib/ical-io.js
index 6899ea6..ac296e0 100644
--- a/src/lib/ical-io.js
+++ b/src/lib/ical-io.js
@@ -111,7 +111,9 @@ export function parseICS(text) {
     method: vcalendar.getFirstPropertyValue('method') || null,
     xWrCalname: vcalendar.getFirstPropertyValue('x-wr-calname') || null,
     xWrTimezone: vcalendar.getFirstPropertyValue('x-wr-timezone') || null,
-    vtimezones: vcalendar.getAllSubcomponents('vtimezone'),
+    // Store raw jCal arrays (not ICAL.Component instances) so the meta stays
+    // plain-serializable for Vue reactivity and JSON snapshot cloning.
+    vtimezones: vcalendar.getAllSubcomponents('vtimezone').map((vtz) => vtz.jCal),
   }
 
   // Events
@@ -185,9 +187,10 @@ export function serializeICS({ meta, events }) {
   if (meta.xWrCalname) vcalendar.updatePropertyWithValue('x-wr-calname', meta.xWrCalname)
   if (meta.xWrTimezone) vcalendar.updatePropertyWithValue('x-wr-timezone', meta.xWrTimezone)
 
-  // Re-add VTIMEZONEs (clone jCal to avoid moving from original parent)
-  for (const vtz of meta.vtimezones || []) {
-    vcalendar.addSubcomponent(new ICAL.Component(vtz.jCal))
+  // Re-add VTIMEZONEs. meta.vtimezones stores raw jCal arrays (see parseICS),
+  // so wrap each directly in a new Component (avoids moving the original).
+  for (const vtzJCal of meta.vtimezones || []) {
+    vcalendar.addSubcomponent(new ICAL.Component(vtzJCal))
   }
 
   for (const ev of events) {