A few effects on the Wild Magic table are spells that normally require concentration. Does the sorcerer have to give up their concentration for these effects to occur?
If so, do they have a choice in the matter? For example, if they're currently concentrating on Witch Bolt, does it automatically break if Wild Magic causes them to cast Levitate?
An effect due to a Wild Magic Surge that typically requires concentration, does not require concentration and lasts for the full duration. You can refer to the PHB Errata entry under Sorcerer.
Wild Magic Surge (p. 103). If a Wild Magic effect is a spell, it’s too wild to be affected by Metamagic. If it normally requires concentration, it doesn’t require concentration in this case; the spell lasts for its full duration.
This is reflected in the official PHB Errata:
If it normally requires concentration, it doesn’t require concentration in this case; the spell lasts for its full duration.
This is further borne out in several designer tweets, notably:
Paul Cloud @CloudOfDaggers @JeremyECrawford Does a wild magic sorcerer need to maintain concentration on spell effects created by a wild magic surge?
You don't need to concentrate on spell effects from the Wild Magic Surge table.
