100% cpu load for several minutes when I clear Yandex mailbox

Steps to reproduce:
1. Open Activity monitor
2. Open Yandex mailbox
3. Select 250-300 emails there
4. Click "Delete"

Look into activity monitor.
Adguard will use 100% cpu for quite some time (2 minutes for me).
It seems as if it was in while (true) loop until connection is closed.