Our Robo used to do that on the flying saucer but they do it for fun I think
. They soon get the hang of how not to fly off it - just make sure there is nothing hard nearby they can bounce off.
I had this saucer plus an upright wheel for our Robo and he used both - I think he enjoyed the saucer most. I can recommend having both. I had the 9” Rodipet cork and wood wheel- spins really easily, can be height adjusted on its stand or screwed to the bars I painted the cork surface with plastikote and it was still like new two years later. It’s not cheap though and trixie also make a 9” wood and cork wheel that is cheaper. They also throw themselves out of wheels for fun - but the novelty wears off quite quickly and they run normally.