The Coming Calamity I was equipped with disappeared.

The Coming Calamity I was equipped with disappeared.
I was equipped with a shield, but I wanted to try out Guiding Palm of the Heart, so I ran around the map and died.
When I checked my equipment list, I saw that The Coming Calamity, which I thought I had equipped, had disappeared.
Just to be sure, I bought The Coming Calamity again from the market, got all the support gems, and returned to the map once more through the portal.
At that moment, The Coming Calamity had disappeared again.

Please investigate the whereabouts of my account and The Coming Calamity.

When I changed characters and selected the corresponding character again, The Coming Calamity was back equipped. That was good for now.
After testing, it seems that when I equip Guiding Palm of the Heart and The Coming Calamity, set the Lightning Mastery support gem on Herald of Thunder, and enter a portal, The Coming Calamity disappears.