FS#3973 - Apple Home Hub not responding

[openwrt-bot]

bohdan-s:

Supply the following if possible:

• Device problem occurs on
  Edge Router X
• Software versions of OpenWrt/LEDE release, packages, etc.
  Fresh install or 21.02 RC4 & RC3
• Steps to reproduce
  Enable "Hardware flow offloading" and "Software flow offloading" under Firewall settings.
  Roughly every hour or so Apple devices will report "All Home Hubs not responding" and then ~1-2 minutes later they will start responding again.
  Reverting to 19.07 or disabling "Hardware flow offloading" resolves the issue.

[openwrt-bot]

bohdan-s:

See FS#3373 for root cause