Respec Ascendancy Skill loses support gems

I play a monk and I had the Ascendancy skill Unbound Avatar activated. For this skill, I added 3 support gems: cold mastery, fire mastery, lightning mastery.

Then I decided to respec 2 ascendancy points into something else, so I removed the point from the Unbound Avatar skill and the node before that and put the points into "Lead me through Grace".

After I did this, the 3 support gems for the Unbound Avatar skill disappeared. They did not go back into my inventory. They just vanished.

I later changed my mind and respecced back to Unbound Avatar, but the support gems did not come back. This is how I realized the just disappeared.