If the Feywild Shard magic item's Wild Magic Surge results in a spell, does that replace the initial triggering spell, or occur in addition to it?

Question

Tasha's Cauldron of Everything (p. 127) includes a magic item called the Feywild shard. The relevant part of its description states:

When you use a Metamagic option on a spell while you are holding or wearing the shard, you can roll on the Wild Magic Surge table in the Player's Handbook. If the result is a spell, it is too wild to be affected by your Metamagic, and if it normally requires concentration, it doesn't require concentration in this case; the spell lasts for its full duration.

This part is the one that some in my group don't agree on:

• My reading: You cast a spell that is being affected by Metamagic. You then choose to roll on the table. If the resulting effect listed on the table is then also a spell, it is separate from the original spell and has the two listed added conditions (Metamagic can't be used on it, and it doesn't require concentration).
• The others think that if the result of the roll on the Wild Magic Surge table is a spell, it replaces the original spell, and the original Metamagic option you chose doesn't affect it.

Which interpretation is correct?

Answer 1

You are correct: it's an additional spell, separate from the one that triggered the Wild Magic Surge.

The effect of the Feywild shard magic item is triggered when you use a Metamagic option. All but two Metamagic options trigger when you cast a spell; Empowered Spell triggers when you roll damage for a spell, and Seeking Spell (TCoE, p. 66) triggers when you make an attack roll for a spell and miss.

In all cases, any trigger that would take effect when a Metamagic option is used would take place at least after the initial spell has finished being cast. This means the potential resulting spell from a Wild Magic Surge coming from the Feywild shard would take place after the effects/concentration of the initial spell have already begun, and would not retroactively cancel the previous spell.

Also of note, the same 2 conditions mentioned in the description of the Feywild shard are mentioned in the Wild Magic Sorcerer's Wild Magic Surge feature (PHB, p. 103):

If that effect is a spell, it is too wild to be affected by your Metamagic, and if it normally requires concentration, it doesn't require concentration in this case; the spell lasts for its full duration.

This, too, is referring to the result of a roll on the Wild Magic Surge table; the relevant portion of the Feywild shard's description uses (almost) exactly the same wording as the Wild Magic Surge feature description.