Document container restart issue and fix

docs/00-CHANGELOG.md

@@ -90,3 +90,7 @@ For detailed history before 2026-01-17, see archived changelogs:
   - LAN DNS redirect updated to use MikroTik AdGuard
   - Old docker-bridge removed (routing conflict)
   - Web UI at http://192.168.31.1:3000
+- [ISSUE] Container failed after restart with 'could not load config json'
+  - Fix: Removed and recreated container, added mountlists, restarted
+  - AdGuard config preserved (on separate mount)
+  - Documented fix in 09-MIKROTIK-ADGUARD-DOT-DOH.md

docs/09-MIKROTIK-ADGUARD-DOT-DOH.md

@@ -241,3 +241,35 @@ Setup script: `scripts/mikrotik-adguard-setup.rsc`
 
 - [00-CURRENT-STATE.md](00-CURRENT-STATE.md) - Current infrastructure state
 - [incidents/2026-01-25-dns-outbound-blocked-after-mikrotik-restart.md](incidents/2026-01-25-dns-outbound-blocked-after-mikrotik-restart.md) - DNS incident that led to this setup
+
+## Known Issues
+
+### Container fails after restart with "could not load config json"
+
+**Symptoms:**
+- Container shows status `S` (stopped)
+- Log shows: `could not load config json`
+
+**Cause:** Container metadata/config.json corruption after MikroTik restart.
+
+**Fix:**
+```routeros
+# 1. Remove broken container
+/container remove [find name=adguardhome]
+
+# 2. Recreate container (will re-download/extract image)
+/container add remote-image=adguard/adguardhome:latest interface=veth-adguard root-dir=usb1/adguard/root logging=yes start-on-boot=yes dns=8.8.8.8 name=adguardhome
+
+# 3. Wait for extraction to complete (check with /container print)
+
+# 4. Add mountlists (note: parameter is "mountlists" not "mounts")
+/container set 0 mountlists=agh-config,agh-work
+
+# 5. Start container
+/container start 0
+
+# 6. Restore MikroTik DNS
+/ip dns set servers=172.17.0.2
+```
+
+**Note:** The AdGuard configuration in `/opt/adguardhome/conf` is preserved because it is on a separate mount (usb1/adguard/conf).