This is intentional, since recent versions had some changes to the way ki blast size works because of ki blasts being so big and their explosions being so big, that they crashed servers.
To put it simply, the Spirit bomb was made small because the configs max size was reached, so the game shrunk the spirit bomb somewhat to prevent lag / server crashing.
One thing to note: The explosion radius of explosive ki attacks have been nerfed severely, BUT you can “un-nerf” them in the configs.
Don’t worry, this change is merely aesthetic, as the damage output of the spirit bomb will still be the same.
(So basically it’ll be the original spirit bomb (the one Goku tried to use against Vegeta during the Sayian saga), small, but really powerful).
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